Hello I Am Concerned About My Knee For The Past

Hello I am concerned about my knee for the past month now i have been having issues with my right knee. It feels very stiff when i bend and straighten it i also can her a crunching sound when i bend it as well as a sharp pain then my knee doesn't always want to unbend quickly it is like it wants to lock in place. I also have an indent on the top of my thigh behind my knee!