Excuse my ignorance, but if photons do not have mass (I assume that is correct) how can they have any energy? If E=mc^2 then M=E/c^2 but if m=0 then E also has to =0. How can a photon have a mass of 0 but still have energy? Same goes for any other elemental particle with no mass but with energy. If I am wrong on any of my statements please correct me.

Also, pardon the overuse of the only equation most laymen like me know, it's the only one easy enough for me to manipulate and think about with my algebra 1 education.