Suggest Treatment For Knee Pain

The inside of my knee has been hurting for the passed few days. I haven't had any accident or anything that would cause an injury, but sometime my knee feels like it wants to buckle sideways. I do sometimes sit with the inside of my right foot on a foot stool (also the knee that is hurting) which makes my knee bend outwards some. I was just wondering if I should have it seen or is it something that will be alright if left alone?