truck would be running in park the starter would engage every couple minutes?

I have e mailed a couple guy here but I need more help, can someone please help me out cause I'm sooooo. Frustrated... I have an 02 F-150, I thought I was having ignition problems cause when the truck would be running in park the starter would engage every couple min. Then it started effecting my fuel pump where I would have to disconnect neg side of battery then 're hook it up every time I wanted to start it. Then when I would put key in ignition a turn to on position the truck would start by itself, Then when I would turn key off and take key out the dash lights would stay on like the key was still in the on position. I changed the ignition switch cause it was also effecting my dome lights and Windows too... I changed it and it stemmed to work for about a week now I was warming up the truck and the starter engaged again.. Now when I turn key off and take it out the dash lights stay on like truck is in on position... Does it every time I try to turn it off, I'm jiggling key and everything but will not go to off position.. I have to disconnect battery cable to shut truck off.. The key Will turn truck on and off just not all the way to off position u know what 8 meann. What the hell Is going on????? Please help me out...