A perine­ural cyst can hurt sometimes. These­ fluid-filled sacs grow near lower back ne­rves. They cause back pain, le­g pain, numbness. The exact re­ason is unclear, but old injuries or gene­s may cause them. Treatme­nt includes managing pain, physical therapy, or, rarely, surge­ry removing the cyst.

To relieve wrist, back, head, and neck pain, focus on maintaining good posture, taking regular breaks to stretch, and applying heat or cold packs. Practice relaxation techniques to reduce muscle tension and consider pain relievers as your doctor prescribes.. So consult your doctor for proper treatment.

It is bit difficult to remove femur nail after 7 years but it can be done and better to take opinion in person. Yes this will heal after removal. 

Next step: consult orthopaedic surgeon doctor

Muscle knots are usually caused by stress. Stress & tension later develops in the form of muscle tightness and discomfort called muscle spasms.
Regarding your slightly high lymphocyte count, if your doctors have reassured you that it is not a cause for concern, it's generally best to trust their expertise. Minor variations in blood cell counts can occur without indicating a serious health issue.