Hello there...., Masturbation now is regarded as a normal, healthy sexual activity that is pleasant, fulfilling, acceptable, and safe. It is a good way to experience sexual pleasure and can be done throughout life.
Masturbation is only considered a problem when it inhibits sexual activity with a partner, is done in public, or causes significant distress to the person. It may cause distress if it is done compulsively or interferes with daily life and activities.
Consult sex therapist...
Sir masturbation doesn't affect bones .it's a very normal activity.there is no link between masturbation and stiffness or bone pain.it could be due to vitamin d deficiency .you can check your vitamin d levels in your blood and share the report with me