For the last 4-5 days i've had a dull aching pain in the right side of my chest and shoulder it becomes sharp and very painful when breathing deeply. ?

Recommend evaluation: In a 21 year old female, heart disease is less likely, but generally should be ruled out as symptoms can be atypical particularly in women. A physician will need to know more about any activities you were involved in with the onset of symptoms, more about your medical history, baseline activity level and diet. A physical exam would also be informative as this could involve muscles/joints/lung.

See a physician: Chest wall pain due to a musculoskeletal strain or sprain from unusual repetitive activity is a likely cause. A viral pleurisy is possible but less likely as the pain would not be dull and aching between breaths, and less likely to localize to one side. A pulmonary embolus with infarction is a possibility if there is: dyspnea and evidence of DVT...especially if on BCP or recent long car/plane ride