Why do I get back pain when coughing or sneezing?

Your back is involved with almost all movements of your upper body, including coughing and sneezing. Coughing and sneezing increase pressure within the spinal canal, which could result in sharp lower back pain. In addition, coughing and sneezing often causes a person to lean or hunch forward, putting them into an uncomfortable position. 

You can also counteract the forward pressure of a cough or sneeze by placing your hand down on a desk or other sturdy surface, to brace yourself. If a cough or sneeze suddenly causes a painful spasm or develops into persisting back pain, speak with your doctor to resolve any underlying causes.