I feel pain in knees when i use a staircase?

Knee pain: We need more details. Is pain worse going up or down? Front or back? Any fluid build up? Any swelling? What about pain when just sitting down. Any trauma? Infection? For now, give your knees a rest for next several days by taking elevator. Continue other activities that won't make knee pain worse. May use otc pain relievers. Go see physical therapist to rehab & strengthen muscles around knees.

Arthritis: When climb the stairs the pressure increase between the knee cap and the thigh bone, so if you have arthritis it show the symptoms especially between the knee cap and the thigh bone.