Donna, Vent Away!
I feel your pain. I know how it feels to need pain meds just to get up in the morning. I am not really overweight, (I could lose maybe 10lbs) I am 43yrs old, and I have had severe knee pain for 2yrs now. (both knees)
I went through all of the shots, therapy, and had them both scoped, but I still have regular sharp pains. It doesn't seem to ache as much after the surgery, but I will still get the shooting pains if I move the wrong way or have to stand for too long. (Not so much of the "all day ache" that I used to have)
I can't say if your OA pain is caused by being overweight, but I can tell you it does happen to people that reasonably fit.