"What causes joint pain, illness, and fatigue?"
I'm in my late 20s and since I was a teenager I have had mystery symptoms that come and go. I have serious joint pain, and my immune system seems to be low because I get sick very easily. I also have extremely low energy. What is wrong with me?
This complex of symptoms that you are describing is concerning, and should definitely be checked out by your primary care doctor as soon as possible if you have not already done this. There can be several causes for joint pain and fatigue, but the possibility that you may have an inflammatory joint condition is definitely higher then average, based on these symptoms of fatigue and serious joint pain. Conditions such as rheumatoid arthritis and lupus can cause symptoms like this, especially if there is associated joint redness or swelling, stiffness and difficulty moving, fever, skin rashes, light sensitivity, or several other symptoms. Your primary care doctor can begin to evaluate this by first doing a good physical examination and then probably orderings some basic blood work in order to determine if you need further workup or referral to a specialist such as a rheumatologist. If the workup checks out ok, there can be stress-related causes of joint pain and fatigue, including poor sleep, as well as other related conditions such as fibromyalgia or chronic fatigue syndrome. However, before investigating these possibilities it will be important to rule out a more serious, underlying medical condition.