No data was given how much exactly is the left ribcage sticking out than the right one. The difference might be minor. Our bodies are not completely symmetrical no matter how it might seem otherwise.
The ribcage is a solid structure with only limited elasticity and its form can not be changed by enlarging of the organs in the thoracic cavity.
You might want to visit your family doctor to see if the difference in the ribcages is significant.

I had the EXACT same problem when I was about 21 years old. Underweight at the same weight, having heart issues, and my left ribcage was sticking out further than my right one! Weird coincidence to discover someone with the same exact explanation. Anyway, I went to the doctor's at that time and they did an x-ray on me and found out that I had scoliosis (a twisting of the spine) from unknown causes. They said mine was pretty minor and may not ever have issues with it. Check out info online about scoliosis (http://adam.about.com/reports/000068_3.ht m), because there are a lot of variations to it. I know someone who had it and had major problems within a year, but it's been at least 5 years since I found out I had it and have had no problems whatsoever and it looks exactly the same as 5 years ago. Also check out this article about fixing scoliosis without surgery: http://www.dailymail.co.uk/health/article- 444901/How-I-cured-twisted-spine.html

Also, I've had a history of having breathing problems with heavy running and swimming, but was never determined to be asthma. Scoliosis is said to have heart and lung problems associated with it:
http://video.about.com/backandneck/Scolios is.htm

My pain is usually either a dull infrequent pain beneath the left lower rib cage, or a sharp pain when breathing in.

I've recently been having the heart pains again, so I think I might be headed to the doc to check it out. They've been off and on for years, and seem to return when I don't excersize enough and increased stress, so now I want to go back to the doctor's and see if something else is going on. Or anyone else out there know anything to add??

I would suggest you find some way to get to a doctor and have it checked out because it's extremely important to check anything to do with the heart!

It looks like I'm not allowed to post links in a forum because they don't want people to advertise (it's a shame that when we try to block out people who are doing bad with rules, we also block out people who are trying to do good), so the ones I posted in the above response are going to be taken out. So I'd suggest just doing a little bit of research using the info I provided and you'll probably find plenty of info like I turned up in a search.

so i have been having so many problems today i was laying down and i realized my left rib cage has somehow grown 2 inches higher than my right side and i need some answers i go to my doctor monday can you help me

im a 20 years old and about a year ago i noticed a change in my left ribe cages hight but i just figured it was from having my daughter so i didnt say anything today i layed down and it is like 2 inches higher than my right side and its freaking me out it has grown more than what it was can you tell me what this could be