Why does my knee hurt when sitting but not walking, and what can be done to relieve the pain?

When you sit for a long time, your knee stays in a bent position and the joint surfaces press together more than when you are moving. One common cause of pain in this situation is patellofemoral pain syndrome, which is sometimes nicknamed "theater sign" because the pain often bothers people after long periods of sitting, like watching a movie. Osteoarthritis, a condition where the cartilage in the knee wears down, can also cause this type of pain, especially when the joint is stressed in a fixed position. To ease the pain, you can try several things: first, do gentle knee stretches and strengthening exercises to help support the joint. Taking short breaks to stand or walk during long periods of sitting can reduce the pressure on your knee. Using a cushion or adjustable chair that reduces knee bend may also help. Some people find that warm compresses soothe the stiffness, while others may benefit from ice if there is any swelling. If the pain continues or worsens, you can use Ubie's free AI symptom checker to better understand your symptoms, and it's always a good idea to talk with your healthcare provider for additional advice and possible physical therapy.