Stiffness is also a result of not moving around enough; resting does not help. A daily walk helps generally, and if you cannot do that, try water exercise. For specific joints and education, get a referral to PT. I do my stretches when I cannot move, drink plenty of water, take magnesium and other electrolytes and am generally ok. AIP (Autoimmune Protocol) diet, Terri Wahls, are suggested. For me, going non-processed, low sugar, avoid potatoes and tomatoes, moderate whole wheat, and dairy has been helpful. Use good oils, like olive, rather than canola, etc. I had a lot of work to do to get glutes, hamstrings and other muscles back to working for me. It can be done!