Before you concentrate on strengthening your knee I respectfully think you need to find out why you are having the symptoms you desribe.
If you have an injury or a problem with the structure of your knee it should be investigated. Given your symptoms it should not be ignored. You wouldn't want to damage the area further.
I'd consult your PCP.
I'm 19, 5'2.
How can I make my knees stronger?
Hello and Welcome to the Pain Management Forum. I don't know your general age which does make a difference in knee issues.
The warmth usually is indicative of inflammation. So you could have a arthritic type of condition in your knee. A "lock up" or popping can mean a problem with your meniscus. It's impossible to be certain actually what may be going on without some imagining of the area.
I would consult your PCP. He/she will probably begin with an x-ray to rule out obvious bone problems and appease the insurance company. If that reveals nothing an MRI may be your next step.
Our knees are complex joints that undergo extreme stress and demands that we place upon them. When they function as designed they are wonderful little machines.... when they are injured or beginning to wear out they can be our biggest nightmare.
Take care of your knee. in the long run you'll be glad you did.
Good luck and please let us know how you are doing.