Why do I have a runny nose every morning when I wake up? My nose feels stuffy and I have to sneeze a lot. But just in the mornings though.

Dust Mites. Classically, nasal symptoms that only affect you in the morning "then get better as the day goes along", are from dust mite allergies. These microscopic bugs live in your mattress, and will usually provoke symptoms overnight. You could also have a sensitivity to other indoor allergens like mold, roaches, and pets.
Bedroom clues. Put on your detective hat and hunt for clues in your bedroom. Dust mites (like dr. R says), down pillows, mildew/mold? Do you sleep with the bedroom window open so that pollen is floating into your bedroom? How about any beloved pets that are co-sleeping with you? Find your clues and solve your allergy mystery!
ALLERGIC RHINITIS. If you are sneezing a lot this time of the year, chances are you are allergic to trees. Start nasal spray at once like Nasonex (mometasone) or Flonase and take decongestant that will not put you to sleep like allergra, claritin, etc.