I've had chills down one side of my leg and pain and I read it could be a blood clot but I'm only 13 and I told my dad and he says its nothing to worry about. Please help?

It isn't likely a blood clot.  You are too young and the symptoms are swelling and heat in the area, not chills.  It sounds more like a cramp.  Try heat, very gentle stretches.  Eat a banana every day or have a glass of orange juice.  Low potassium leads to muscle cramps and a banana or juice is a good source.

Is your leg swollen, red, hot to touch & painful???  Are you short of breath or do you have difficulty breathing?  If you answer no, then you don't have a blood clot.

It's better if you don't go on-line & try to self diagnose yourself.