pain in lower left ribs

in febuary of 2009 i went to the er for extreme pain in my chest. they evaluated me for a heart attack even though i am only 27 years old. they did a ct scan to see if they could find the cause they where not able to find the cause for the pain i was having but in the scan they found that i had a bening 9mm nodule in my left lung. about a month after this i started to have pain on my left lower side around my ribs. i thought at first i may have pulled something or injured my ribs but when i put pressure on the area it has no affect. then just recently the pain became so severe in that area that i ended up in the er again. they did another ct scan and found that the nodule had not changed and they where not for sure what was wrong with me and just sent me home. i am still having the pain but not as bad. i would just like to know if there may be able to give me any suggestions on what may be causeing this pain.