I Have Severe Spinal Stenosis And Have Been Under Pain

I have severe spinal stenosis and have been under pain management for several years now. I had a lapectomy two years ago come October. My sciatica was so bad that I could not walk. I still have a lot of pain, but it is better than it was. For the past year I've had increasing pain in my joints. My hips,neck and shoulders are the wòrst but the elbows, knees and heels are catching up quickly. My doctor suggested targeted drug delivery and I am getting myself prepared for it.

My question is this:
Is it possible that I have some type of infection that is causing all this joint pain and stiffness, and if so, what type of infection could it be? I rarely run a fever but I do get flu like symptoms and get extremely tired. Sometimes I need three naps a day. The pain wears me out.

I thank you for any thoughts or suggestions you can provide for me.

Barbara