lump in right testical and dull ache

Hi im 23 years old about 2 weeks ago i found a tiny lump on right testical situated at the top left i have had dull ache in my right testical lower abdomen and right groin it hurts most when im sitting down ive been to the doctors he said its nothing but i feel he has not done a proper examination ive been the doctors 3 times had 3 diffrent types of anti biotics not worked painkillers also not working does any one else no what this could be really starting to worry me