Chrysler 300 touring

Hi. I have a chrysler 300 touring 2005. Everything has been running great. went to get gas after work,got back in to leave and would not start. wouldnt turn over or anything. 40 mins later it started. ran fine. drove to work today and ran errands. happened again. took over two hours than started up and drove home. Does anyone know what can be going on.. Thanks.