I Had A Wisdom Tooth Removed 4 And Half Months

I had a wisdom tooth removed 4 and half months ago. 2 months ago there was swelling on the jaw and i was prescribed anitbiotics and and it has happened 5 times now after that, usually lasts a week. I had Amoxicillin course 2 times now and i had x-rays taken twice of the area. They cant find any problem, the bones looks like it is healing quite well. No internal signs of infection. Gums and roots look normal. What could it be?