Knee pain

I have had an irritating rather than debilitating pain in my right knee now for the last 3-4 months. I play soccer once a week but the pain came on during a 3-4 week break between games. The pain seems to be inside the knee and is worse in the morning or when I have been sitting or kneeling for a period of time. It’s painful if I sit with my right leg crossed over my left, if I tense the leg whilst it’s bent or bent inwards, and particularly so if I press against the back of the heel (i.e. when I kick my shoe off with the other foot). It does not really bother me when I play soccer, but it’s always worse after a game. The only thing I can rule out is medial ligament damage as I suffer from this in my left knee.