Is swimming good or bad for osgood schlatter disease .. ?

Not really: When u swim u kick and put force across the knee and = irritate the tib tubercle. Rest is the best, and significant vacation from the cause, football, buckets, soccer et al. Ice after activity, and there are some bands that stretch over the patellar tendon that may help some, but more 4 jumpers knee. Stop growing = gone. Lump stays, pain goes.

Good: Osgood-schlatter is a condition involving a portion of the tibial growth plate at the insertion of the patellar tendon. It is associated with tight quadriceps (especially the rectus femoris). The best treatment is lots of stretching, nsaids and rice. It resolves when the growth plates close. Swimming is unlikely to exacerbate the issue and is a good way to stay active.