Hi, I Have Started Having Pain On The Medial Side

hi, I have started having pain on the medial side of my knee. It feels bruised but there is not evidence of bruising. It hurts when I walk up and down stairs and also feels kind of weak at times. I don't have a mechanism of injury that I can think of. The area hurts (like a bad bruise) when I put pressure with my finger on it. I have had this pain for about 1 month now and nothing seems to be helping. I have tried some NSAIDs and icing/heating.