Testicle pain after swimming breast stroke?

Ok so im 15 and am a swimmer. I was swimming breast stroke and all of a sudden my right testicle started to hurt and it got worse as i kept swimming. It could be a pulled groin but i don't think so because it feels like its in the testicle more than the muscle. Its not a torsion because it only hurts when i use the groin muscle, and the pains not excruciating and it hasn't been getting worse. Any ideas on what this could be?