Stupid starter!!

[MJN]

I need to know what is going on here. After getting warm after driving about 30 minutes and shutting off the motor, the truck won't start after like 5 minutes of sitting. There is nothing, like a dead battery but everything else works. If you let the truck sit for about 30 to 45 minutes depending on the temp outside it will fire right up after the engine is cooled down. The engine never gets very warm and always stays in a normal spot on the guage. Could the exhaust be baking the starter so it won't even engage? I recently changed to manifolds and before had headers and the headers were almost touching the starter. Could they have fried it? The stupid thing is only six months old and should last longer than that. Lately it has been in the 90's here and humid and has only done this twice so far. Thanks for any help!