Is it usually normal to go see a third orthopedic surgeon? i really have been having a lot of instability in the knee with shifting kneecap help

No: Not normal by any means. However, based on your questions over the past few weeks, you have persistent pain despite surgery and several different doc appointments. If the 1st and 2nd orthopedists agreed with each other and gave you similar recommendations, then likely they are giving you solid advice. If they did not agree, then a 3rd opinion as a tie breaker would be reasonable.

Physical therapy: Did any indicate physical therapy to resolve it? This might be a good choice.

Third opinion : If you've been diagnosed with an usual condition, you may need to. For not so unusual conditions (most cases), a third opinion can sometimes confuse you more than help. If in doubt, talk with your doctor as he or she may guide you in deciding which path to take.

Reasonable to do: Most ortho problems do not require second and third opinions, but kneecap pain and kneecap instability are difficult problems that many ortho surgeons are not comfortable nor expert at handling. Many docs are not up to date in knowledge and still perform "older" surgeries that have proved not to work well. If possible, you seek out a surgeon who specifically specializes in patellofemoral disorders.