Every thing is explained by Solace21. You need medical treatment. Luckiest part is that the problem is treatable. Shyness in critical situation may lead to serious health problem. Heed the advice given.
Hi Jhonnyboyo,
Some times such pain can come if one of the testicle retracts inside and due to the pain, the ejaculatory spasms does not occur. However, if you are experincing ejaculatory spasms and no semen comes out, it is mostly due to retrograde ejaculation. Other reasons for pain may be due to some inflammation in the spermatic chord or an inguinal hernia.
In any case, since you have found out a health problem, you have to get it checked by your doctor. I fully understand your embarrassment to discuss your problem with your parents, but you need to overcome your shyness to find a solution to your problem. May be while talking to your mother, you may talk of occassional pain in your abdomen, but while telling your doctor give full details as you wrote above. You should also ask your doctor about the bump on your penis. By the way, do you get night emissions and feel pain at that time?
Good luck, do see a doctor, do not shy away,
Solace