when I lay on my left side I get stomach pains

It could very well be IBS (irritable bowel syndrome) or other condition.

If it is IBS, there isn't any medication for it; it's a matter of getting the colon to settle down. It's important to get fiber in the diet, the best way is to drink some citrucel or metamucil (recommend the citrucel, no excess gas) every day, don't miss a day. It'll stop any constipation, and reduce the spasms that are causing the discomfort. You may have heard the term "spastic colon", which it was called before IBS.

It is also very important to get PLENTY of rest, excercise and avoid stimulants of any kind. Excercise will reduce anxieties and stress a lot!

You should visit your doctor for a correct diagnosis.