i’ve had trouble with my knees for about a year now, started when i played my last year of ball in highschool… anyway i had to quit squatting, which sucked, i can do hack squats however, dunno why… but anyway the other day i went to the gym at my new university and did some leg extensions, the thing is set at an angle less than 90 degrees, no matter how light it was i couldn’t move it without incredible pain in my knees, i had to reach behind me and pull the cable down with my hands to get started and i never let them go past 90 degrees…sooo my question is what is going on here? (i never did leg extensions before because i always worked out at home b4) shouldn’t i be able to do extensions without pain, i mean it’s not exactly that hard of an exercise.
You need to see a good orthopedic surgeon ASAP regarding your knees. If you're in San Jose/Stanford/San Fran area, I'd recommend Dr. Michael Dillingham. He's from Stanford and works at SOAR clinic, and he's an excellent orthopedic surgeon.
I also had knee pain and had to take two MRIs (the first one was inconclusive or whatever...). The second one revealed that there's nothing the surgeon could do to fix (no structural damage), so he recommended that I do physical therapy to strengthen my left knee because I do feel pain when there's any kind of pressure on my left knee.
Good luck. I hope it's nothing serious.