I felt pain in my left wrist when i was turning a door knob but i didn't hit my wrist, it hurts when its bent/ has pressure what is the problem?

Tendonitis: Sounds like tendonitis. I would suggest rest, ice and OTC NSAIDs

Wrist sprain: Sounds like you sprained your wrist. Avoid strong gripping or repetitve activities with the hand for a few days. A wrist splint may also help along with some anti-inflammatory medication until it feels better.

Tendonitis: Sounds like a tendonitis problems like Dequervains. You didn't acknowledge an injury and usually a sprain is caused by an injury. Tendonitis is more of an overuse type of problem often caused by overdoing normal daily activiities.

Possibly tedonitis: Try icing it, resting it, and an OTC NSAID if no contraindications and if not better see your doctor.