Trying to get info about a knee injury i have?

I have a knee injury that has me confused. I am considering going to the doctor to have it looked it, but I want to make sure it is worth the trip (I hate going to the doctor for nothing). I play softball, and my knee only hurts minimally while I play. It's the next day that I experience a lot of pain. The day after a game, I have very limited flexibility in my knee. The pain is in my right knee, towards the outside of my leg. From what I have looked up, the pain seems to be in the general area of the lateral collateral ligament. I do not think it is an injury to the ligament, as I experienced no "pop", no swelling, no immediate trauma to the area. I have no issue bearing weight on the injured leg, but when it is in a bent position, I can not push off (i.e. climbing/descending the stairs). Some movements that most noticeable hurt seem to be when I try to remove my foot from my shoe, or when I try to lift my foot from the gas pedal to the brake while driving. Any insight would help, thank you.