What Causes Burning Sensation On Hip Skin With Rashes?

Hi. I have a burning sensation on the skin of my left upper hip, on the skin of my left thigh and groin. This started 5 days ago, and after 2 days I got rash on my shin close to the leg, it looks like burned spot. For the past to months I have practiced thai boxing. Sometimes I have also sharp pain in different places on my left leg. I appreciate any help and thank you very much. Medi