The top of my ears are red and swollen and hurt could it be from the sun?

Possibly, yes: Strong possibility if you have been out in the sun, especially if for a long duration. Many hats, e.g. ballcaps do not protect the ears. And tops of ears are most at risk, both from acute sun effects, as well as chronic or long term affects such as skin cancer. Treat the acute sunburn affects with burn or sunburn creams and oral acetaminophen/ ibuprofen for discomfort. Use a hat with wide brim.