Well the day after I had sex I found a white pimple like under my shaft and I tried 2 pop it and I can't it hurts and won't pop what should I do ?

Leave it alone and go see your doctor.

Tick

Most likely it is just an ingrown hair. You can try putting some moist heat on it, but by all means don't "pop" it. By popping it you open it up leaving yourself open for infection.