anyone know how to fix a problem with my earphones?

when i plug my headphones or earphones in to my laptop (macbook pro) one side is significantly quieter than the other side. i have tried different sets of earphones on other devices and can confirm it is my laptop. any ideas on what i should do? i keep my laptop in very good condition and dont have my earphones plugged in to my laptop very often. this is a major inconvenience as i enjoy using my headphones for car journeys or films and would greatly appreciate any help, thanks