Do I have Colon Cancer?

For the past couple of days I have been experiencing pains in my upper left abdomen along with the right side of my abdomen. The pains are not constant, they come and go and the pains are not present in both places at the same time. I’m really worried. My parents have just told me that they are growing pains and that they will go away on their own. I’m 15 years old. Also, last week I was also experiencing pain in both right and left sides of my lower back. I’m afraid of anything to do with Cancer, and even dying. Please help! Thanks.
Oh, I almost forgot. In January I was constipated for 3 weeks and had to have an enema. However, I have been passing my waste normally since then. I don’t know if this helps.