I have no idea if you're new to this or not. You may not need any advice! But I'd hate to leave you floundering on your own if you feel helpless, not knowing what to do, or if there is anything you can do, so I'm going to write as though you do. If you don't, then please just ignore me
First of all...document ALL your health issues...a bullet-point list is fine to start with. Sometimes things you don't expect can be contributing to your main problems...like unattended allergies can add to fatigue, for example. Anyway, once you have your list, take the main ones (I assume back pain and fatigue) and detail them as much as you can. Make note of when your pain is the worst (and when it's at it's best, if you've noticed it being notably better at any time). When you wake up? After you mow the lawn? At bedtime? In the night? When you're at your desk? Etc. Is your mattress firm? Are you a back/side/stomach sleeper? Do you move much in your sleep? Do you sleep well? How many pillows do you use? Do you use a body pillow? If you're a side-sleeper, do you put anything between your knees to keep your hips aligned properly? Many of these things can affect both your back and your fatigue.
Once you have a clear picture of your back pain and your fatigue, see an accredited health care professional, whether mainstream (such as a doctor or physical therapist) or alternative (like a registered herbalist or accupuncturist, etc.) or someone in-between, like a chiropractor or massage therapist. Ah, btw...the hospital emerg department seemed to take me more seriously when I said my chiropractor told me to go to the hospital, last week, due to a pinched sciatic nerve. They got me seen fairly quickly and even gave me a shot of industrial-strength anti-inflammatory...like turbo-charged Advil...to squash the acute attack immediately so that I could get on with rest and therapy. So that was helpful for me, too. But anyway! Go see as many health care professionals as you can and get their advice on things you should do or not do. They often have product recommendations, too. Things like posture-correcting items, ergonomic chairs or seat cushions for back or bottom, exercises to strengthen weak areas of your back, stretches to loosen tight spots, etc.
So, soak up every bit of advice you can get and try it out. Doctors are NOT always right. I find it's pretty much 50/50, tbh. I always end up having to take charge of my own issues, but seeing a professional is a necessary first step. If you can even get a
name for your problem (like piriformis syndrome, in my case, and MS-fatigue) that's very helpful in finding more info on your own.
Once you've got your problem identified, do your best to implement the best advice you've managed to gather. Really do the stretches and exercises a doc, therapist or chiro has recommended for you. Do them religiously! Imagine you're gonna get a big prize for best-taker-of-advice, lol. (I literally just went and did mine again when I wrote this, lol.) I have most of my life been concentrating mostly on stretches, but am so naturally flexible that I find they don't work that well...I have to OVER-stretch to feel anything, which can cause problems instead of helping. I thought exercises might make it worse since some of my muscles were being troublesome, but I was desperate, so tried them anyway, and they actually help more than the stretches!
If you already know what your issue is, like I know I have piriformis syndrome, then the internet can become quite helpful, if you're judicious. The doctor I saw at the hospital recommended 'Dr. Jo' on YouTube for me...told me to search 'Dr. Jo Piriformis Syndrome' and to do the stretches and exercises in the video that'd pop up, which I have done, and it HAS been quite helpful. Oh, and she said to use ice a lot, and heat if it was helpful (heat can make things worse, depending. Heat relaxes and expands, ice contracts. If you're already swollen or inflamed, heat is bad! But if my muscles start spasming in response to the nerve being pinched, ice on the sciatic nerve area and heat on my leg where the muscle is spasming is a good combo.
Uh, word of warning, though. You may already know well, but if you don't...researching things like diet and supplements for health online is a minefield of the absurd and sometimes even the dangerous. Supplements in particular. I'm not saying don't do it...simple though it is, peppermint is the best thing I have ever found for IBS symptoms, and I first read that online 20 years ago...but be very suspicious of everything you read. Always check the source of the information. NEVER trust someone who is selling something or in any way getting money out of you taking their advice. So if ABCsupplements.com is telling you that shark liver oil will cure your migraines, fix your back, make you sleep well, and give you beautiful skin to boot...run away. They just want your money, and it's complete hogwash. At best: useless. At worst: harmful. I'm not saying following a specific diet or taking certain supplements is wrong or bad...in fact I know first-hand that they can be very important...just that it's one of the most dubious things you can possibly search the internet for, so you have to make sure of your sources and only go with what you can find multiple reliable ones for. Like if Harvard Medical, John Hopkins and the Mayo Clinic are all recommending, say, olive oil and salmon for your heart problem, then you can take that as good advice.
Anyway, my summary is that in my nearly 40 years of experience at dealing with chronic health problems, I've found that you have to aggressively fix yourself. Health care professionals should be treated as valuable resources, but ime, you can't rely on them to fix you...they never will. They just provide a helping hand and a bit of guidance, and once in a rare while, you may even get a helpful prescription out of them. But unless you have a broken bone, or need surgery, or have something a pill can fix, all the actual work is on you. (It'd be so nice if this wasn't true!) I'm sorry if this was annoying rather than helpful. Though if it was, you definitely should have stopped reading before now, lol.