Vitd very low. age 30. did not have nutritious food during growing years. entire left body(head-toe) in extreme pain for 6yrs. what tests should i do?

Vit D: Vitamin d can be associated with chronic muscle pain. I don't know how low your level is, but please talk with your doctor about replenishing it. You might want 5-10, 000 iu/day for awhile, depending on your level -- and then recheck in 2-3 months.

Longstanding issues: The best bet is to see a doctor to tease out the most serious or most important issues. Testing can be based on the most likely or most serious problems while trying to sort everything out.