Re: on the left side of my lower abdomen is a bulge/lump/knot... please help!
Most people are born with their hernias. They start showing when their activities increase, whether it's sports or occupation. Supports don't work and are only recommended in the very elderly with too many medical risks to undergo surgery. General surgeons repair hernias. It's a day procedure; takes about an hour, but you'll spend at least half the day at the hospital. You can choose not to repair it, but if a part of your bowel gets stuck in that opening and strangulates, you'll get a big zipper down the front of your abdomen instead of a little 3 inch scar in your underwear line for an elective repair.
If it is more in the crease of where your abdomen meets your leg, it could also be a lymph node. Considering you've had treament for infections in that area, it is a real possibility. Another thing that 16 year-olds are more prone to getting lymphogranuloma venereum, usually a sexually transmitted disease, but can be picked from sweaty gym benches, etc.
Be well, see your doctor soon.