I believe you've asked this question before. The answer is the same. See an orthopedic specialist, your family doctor can refer you to one. Pain in the knee means there is some sort of damage. Dr.Scholl's may alleviate some pain but isn't going to repair damage.
I made a decent living putting my body through hell. Eventually, I would have to pay the toll and I did. A few years ago I did my usual workout which includes squats of 500+ pounds. The following morning, I had a pain in my ass...literally. There was a pain in my right buttock that felt like a bruise. I treated it as such and ignored it. The next day it felt like someone shot a molten bullet in my cheek. Through my experience and education about the body I quickly knew it could be something other than tissue damage. I went to the doctor and was examined and there was nothing wrong locally. More tests concluded that I had a herniated disc that was pressing a nerve in my spine that was wired to my ass. More pressure, more pain. I ended up with minor back surgery to repair the problem.
When you get pain that you can't explain, see your doctor.
You ask me why I lift, I wonder why you don't.