POSSIBLE PANCREAS ISSUES TOO,,YOU A HEAVY DRINKER?
Well, the good news is that the appendix is on the right side. http://kidshealth.org/parent/infections/stomach/appendicitis.html
http://wiki.answers.com/Q/On_what_side_is_your_appendix
That said and referenced, the pain on the left side is more likely to be your descending colon. You should definitely see a doctor about this. I have IBS, so I know what I'm experiencing when I feel pain in my colon. But, since this is sudden and new to you, you should definitely see your doctor.