positive battery cable getting hot

[collins10672]

i have a 1995 silverado that has been setting in the garage since december without being started.since i have owned the truck if you leave the battery hot cable attached to the battery it will drain the battery in about 3 weeks.so i keep the positive cable unhooked.i attached the cable yesterday and the underhood light burned strong,but it would not start so i tried to boost it off and still would not start.so i take the battery off and charge it all night long and put it back on the truck this morning and still would not start.when i put the battery back on the positive cable is getting hot.also i have noticed that the key switch seems hard to turn.the truck is a 4.3 5 speed.any input and help would be greatly appreciated.thank you