Painful lumps on right side groin. doctor gave antibiotics but did nothing and he won't do anything else. what could it be? there's also a little gap.

Unclear: It is unclear what exactly is going on. Since he prescribed antibiotics, your doctor seems to think this is due to an infection, but your question implies that antibiotics didn't help. Perhaps wrong antibiotic? Perhaps something else not due to an infection? Hard to say. See another doctor, possibly an ob/gyn, since they are in the groin. Sti testing may be necessary.