Canadian chevy

Have a 2014 Silverado 1500 5.3, truck starts and drives great all day everyday! But when I am pulling an enclosed trailer or boat if I turn it off for any reason (in a mall parking lot, got to where I’m going, or to fuel up) it won’t start and I have to wait 30-45 mins for it start. I have driven all day and shut it off for fuel without trailer and it starts fine, I have a new battery installed in the fall, I have checked connections, I even unhooked trailer electrical to see if that would work but it doesn’t. I use the tow/haul mode but still won’t start if I don’t use it, today I drove 20km and shut it off and it took 30 mins to get it started. Engine temp, oil pressure everything is in normal operating range. When I turn key my truck powers on (radio,lights, dash,etc) but when I turn to start there is just one “click”. Any feedback would be helpful as I don’t want to buy a new starter if it’s something else ( after posting I realize this is in the wrong category but an engine is an engine)