91000 miles 5.0 steering seems to get a little harder. Have to turn wheel to straighten out. Any ideas what can cause this?

 

Your vehicle very likely has electric power steering assist. Most placed not equipped , info ,experience, to service electric power steering .
Suggest you consider a dealership check it out.

 

You just need a simple wheel alignment. If your truck is lifted then buy a camber kit in advance just because the shop don't carry that and a 2nd visit or double payment is required. You can always return if it's sealed and brand new still. The kit you need is just eccentric cam bolts for the lower control arm to make it more adjustable than factory.