I noticed a sore spot in groin area one morning, Caused me to limp slightly, went to doc next day and he said it was a swollen lymph node and asked me if I had any sores on my leg. I had not at the time but that same evening I noticed a large, tender pimple on the back of my right knee area. It has been draining and looks really bad. Any coalition between the two?

My son has had the same issue, ongoing for the last 6 months now. I've been scouring the internet and so far it sounds like it's either a Staph infection or Cat Scratch Disease.

A pimple is in essence a bacterial infection of the skin. A swollen area in your groin is probably your femoral lymph node. It is possible for it to cause it. However you question was asked in September if it is still swollen after your pimple is long gone head back to your doctor as it could be a serious issue.