Pain behind the head of my penis

I have a pain 1/2 inch behind the head of my penis, not on bottom or left side but in between. The pain is not bad but very annoying and it comes and goes. Sometimes it lasts for a few seconds other times longer. There could be several minutes to hours in between pain. No other STD symptoms….none. Happened one other time while working in China a year ago and lasted for a couple weeks and went away. Chalked it up to weird foods in a foreign country but now its happened again about 2 weeks in. Just wondering what the cause could be.