I used to do masturbation regularly and one day during the climax of ejaculation I stopped, since after tht day semen also comes along wid urine thr?

IT IS PROBABLY NORMA. If you have not had unprotected sex than what you see in the urine is normal masterbation will not cause any i;; effects at your age but if there is any symptom like pelvic pain, burning or pain during urination, than consult your doctor.
Prostate gland. If you do not empty your prostate gland through ejaculation then nature finds a way to get the old aged seminal fluid out to make room for fresh fluid. Fresh fluid is necessary to keep sperm alive. This is normal.