Whenever I am about to get on large ride such as a roller coster my lower back beginns to hurt could this just be nearves?

Back pain. This is your back telling you that roller coasters are bad for you. Seems like your brain has forgotten and has made your back take over the decision. See if back exercises and staying away from roller coasters works, if not, there might be a medical or a mechanical problem with your back. Ask your doctor or go on line to get williams esercises. But if you are over 50, get an examination.