Ever since I ran a mile at school about 2 weeks ago, I ve had very bad pain in my right knee whenever I squat down, or try to stand up from sitting down. The only way I m able to do so is by putting all my weight on my left leg. Also, whenever I have my knee bent for long periods, like 20 minutes, it will begin to ache and get worse and worse until I straighten it again, and when I do there s sometimes an excruciating pain that lasts for around 10-15 seconds. I can t feel my knee and pinpoint an exact location of where there s pain, and there s no swelling either. My knee also has painful pops and cracks if I don t straighten it periodically. I ve searched online but I haven t found anything that really matched my symptoms, and I don t know if this is really something to worry about. Should I see a doctor?