I get brief pains at different times in my groin, hip, knee and my foot all on my left side. No swelling but bothersome. Any idea?

Vague but... What i can tell you from experience is that i had similar sensations, and finally ended up with a herniated disk in my back. Since you said that you also have back pain, it could be the start of or you already have some disk issues. Don't wait and get it checked asap.