I am facing severe pain in my knees while climbing stairs.

See details: There are several causes of knee pain but pain basically with stair is consistent with an issue involving the kneecap. See an orthopedist and have the knees evaluated.

Rest a lot: Try MOtrim 600 mg every 12 hour if no improving go to see an Orthopaedic and a aNTI-inflammatory treatment for pain. .MRI of knee will help to find a diagnosis.