Based on my symptoms, what is the possible diagnosis?

In a young male I suspect a lower urinary tract infection most likely a prostate infection or urethritis. See your physician or a urologist so that appropriate testing &treatment will be obtained. If you engaged in recent risky sexual intercourse, this has to be brought to the doctor's attention and tests for STD will be ordered.

I agree that a urinary traction infection a problem with the prostate could be occurring. Men often get these from sexually related infections and anal sex. You could have noninfectious prostatitis. See a urologist, if you can see one soon go to an urgent care.