Latch won't retract into my door unless I turn the knob
I think a little lubrication will fix this.  Try turning the knob so the latch is retracted and spraying a little lube into the hole where the latch goes.  Use the little straw that comes with the spray can, and get it as far in as you can.  Spray very sparingly.  Then turn the knob back and forth to work the latch.  See if it's working any better, and repeat if necessary.  A shot in the keyhole as well won't hurt, while you're at it.  

If this doesn't do it, you may have to remove the doorknob / lockset and remove the latch to apply the lubricant more thoroughly - but I doubt it will be necessary.  

For the lubricant - some people agonize over what to use, I do not, WD-40 or a good quality silicone spray will be fine.