The most frequent causes of running injuries arise from what is known as "training errors". These include poor running shoes, poor running surfaces or terrain, and rapid excessive increases in milage or speed. Any, or all of these, may have been a factor in your recent episode. If so, a short rest, ice, and careful return to activity should suffice.
You have not given a history of injury, either recent or remote, so I assume this is not a factor. In addition, there is no mention of swelling, limitted motion, or deformity. However, I am concerned that your pain is continuing, despite that fact that it seems to be tolerable.
If your pain does not resolve after several days rest, or if it worsens, or if it goes away and then returns when you attempt to run again, you should seek medical attention. Good Luck!
Now that you mentioned it Doctor, I had a history of trauma of my left knee. About 6years ago, I fell while climbing the stairs and my patella hit the edge of the step pretty hard. I had an X-ray but the doctor said no fracture. But I still had to rest and take it easy for about 3months.
The injury had never caused any trouble before now though.
At that time, you may have injured the cartilage behind the patella, and over time this condition may have worsened. If so you have developed a sort of post traumatic chondromalacia patella. Or, it may be completely unrelated. In any case, I think a thorough examination including X-rays and possibly MRI is probably in order.
Hello, Pain associated with chondromalacia patella would also be exacerbated with sitting with knees in a flexion position aka 90 degress to the hip after long peroids of time such as at the cinema. As a possible cause, malt-traction of the patella tendon associated with weakness in thr VMO.