You could also have an irritation of the lining of your lungs, called pleurisy. It comes with very painful breathing, sharp in quality. Definitely talk to your doc about this, if it is pleurisy, the treatment is usually NSAIDS such as motrin. Another thing it could be is a spasm...you'd be surprised at how painful a spasm on your rib cage is! Sunny :)
Tightness is defintely a sympton. Not so familiar with the sharp pain. Asthma is a tight feeling... you wheeze, you take short breaths when you are actually having an attack.. you struggle to get air... can cause lots of coughing.. a bark cough.. or even a dry consistant cough... mostly triggered by allergies, or atleast mine are. You cannot take in a deep deep breath without coughing when you are having an attack, and sometimes when you are Ok.. it really takes a toll on your lungs. Go to the doc and get checked out you dont want to wait until you cannot breath like I did to get diagnosed and treated.
I am 21, and it was NEVER detected until now.