I have a 1 year old American Bulldog who is otherwise healthy. Last week she and I was playing and she ran into me we fell over and I pulled her into my lap she yelped and stood up but wouldn't put weight on her right back leg. There appeared to be some sort of buldge around her rib cage it was hard to the touch but did not seem to be tender to her. I massaged it and her hip and after about 5 minutes she was back up and running like nothing was wrong. Yesterday she was running on the ice and fell... she barely whimpered but refused weight on it again.. I rubbed it and we started back to our house, she took a few hobbles then refused to walk any further. My friend carried her to the house where we put ice on the hip again I noticed this knot on her side... after rubbing the thigh and hip the knot went away and again she could walk on the leg... She seems to be favoring it and is not quit as "active" as normal.. she seems to want to play but when she jumps around the knot returns and she can't put pressure on the leg again... anyone ever seen this before?

Yes, when my dog tore her cruciate ligament. Your dog is injured. Take her to a Vet - same thing you would do if you were injured. (She was a Rott)