Knee pain


I found Fitness Blender about a month ago, and I'm hooked! Unfortunately, I think I was a little too enthusiastic about the HIIT workouts because I've done something to my knee. It's right behind/on the kneecap.

I haven't been to the doctor yet because it's not terrible. I don't even notice it much walking around during my normal day. However, any time I try to bend my knee and put weight on it at the same time, pain shoots through my kneecap. For example, climbing stairs. I've never had this kind of pain before. I had tendonitis in my other knee in high school, but this feels different. So far, I've tried icing, ibuprofen and resting it. No exercising at all for nearly 3 weeks. I tried walking today with a bit of incline on a treadmill (while wearing a brace) and that was ok. I couldn't run though and definitely can't do any lunges or squats. Has anyone else experienced this type of knee pain before? Just to be clear, I'm not looking for official medical advice. Just an idea of what this might be. Thanks.