swelling and round thing.

Hi i'm 19(female). Last week when i woke up I felt pain at upper part of thigh.When i check the place it's swelled and i feel pain when i pressed it. Slightly opposite of the swelling i found small round thing(section where thigh attach with vagina) but it did not cause any pain. The swelling is hard and few days later the pain gone and swelling reduced slightly. The round thing got smaller(maybe not sure). Is it some sort of nerve problem or something else?