Pain at back of knee

There are two main reasons for you experiencing pain in the back of the knee. This could be a serious problem and you have to get it checked out.
Cyst: One of the main reasons for experiencing pain in the back of the knee is due to a cyst. The formation of Bakers cysts is a big problem and this might affect you movement. You have to check with your doctor as soon as possible.
Outside the knee: Sometimes pain in the front of the knee can be felt in the back of the knee. This could be a problem of the kneecap.

Hi Mantha... I agree with Bhavya. Cyst in later stage can pop out and would give a bag like appearance . ALso, there can be also a problem with your back muscles like hamstring muscles . Try stretching and hold it for 20 counts, if the pain increases then you consult doctor or id pain relieves repeat it atleast 5 times in a day. The inflexible hamstring muscle might also lead to pain in back of knee .