I injured the thigh muscle on the inside of my leg next to the knee-cap. I was kneeling with the knee of that leg on ground and leaned forward to grab something. I felt a burning sensation in that area I described above. After the injury my knee would make a popping sound when I straightened it out. The injury happened abut 8 months ago and is better but still not 100%. I was exercising on my stationary bike the other day that injured area feels strained. Should I stop doing exercise that impacts that muscle? And could this be a serious injury? I thought I just pulled a muscle.