Hello i feel a discomfort around my knee joint. i dont feel pain, no swelling. there's creptus sometimes. what i noticed is when i start to exercise, the discomfort goes away & when i stop 2 or 3 days later, it comes back. any idea what it could be?

What part of the knee there is discomfort is the key to knowing what it is. That pattern of going away when you exercise on a regular basis and coming back when you do not is characteristic of patellofemoral syndrome. I am assuming that is what it is with the discomfort being more going up and down stairs. Patellofemoral syndrome is irritation behind the knee cap. Look that up and what to do!