Knee pain by an accident. Should i do?

2 months earlier i faced with an accident while got up an auto rikshaw i step up my leg inside the auto and my left knee hit with the seat-rod.that time i feel a deep pain in my knee and i cannot bend my leg for few minutes.i was feeling as if my knee locked but taking a rest beside the footpath for few minutes then i was able to walk in slow motion and came to my home and give some ice to that place and feeling some relief after few hours.then next day i cannot feel any pain on my knee.but after passing 2 months now i feel some internal pain on the same place (bearable) sometimes, though it does not create any problem when i walk but a soft pain i fell when i am sitting in a place for a long time either in a bed or a chair.so please suggest me what should i do?