Hi, Thanks for posting in HCM. I understand your concern. Masturbation is a healthy physiological phenomenon. It is a natural and normal act practised by most men. It does not cause any adverse effect like premature ejaculation or erectile dysfunction or decrease fertility. On the contrary, it might help to release psychological stress and produce good quality of new sperms, when done properly. However, it should not be done too frequently as it can cause physical exhaustion. Back pain what you are experiencing could be related to it. Kindly take analgesic medication like Ibuprofen. Along with it, you can do few back strengthening exercises and apply topical analgesic creams. Also, supplementation with Calcium would also be helpful. Gradually, your symptoms should get better. Hope the information provided would be helpful. All the best.