Pressure: The nerve has little padding over it – direct pressure can press on the nerve
Stretching: Keeping the elbow bent for a long time can stretch the nerve – this can happen during sleep
Anatomy: Sometimes the nerve does not stay in place and snaps back and forth over a bony bump as the elbow moves – this can irritate the nerve. Abnormal swellings within the cubital tunnel may also press on the nerve

Avoid actions that cause symptoms such as pressure/leaning on the elbow

How to relieve the pain

• Take breaks in between work 
• Use elbow pads
• Wrap towels loosely around the elbow
• Position pillows to keep the elbow straight when sleeping
• Wear a splint to avoid bending of the elbow
• Many different types of splints are available