Possible to develop sinus infection/cold overnight? Felt physically great at night, then woke up w/ sinus pain, yellow stuff blowing nose, body aches

Yes. Although it should precede with some fever and sneezing, but in some people it can develop almost overnight. You may have allergy issue and the infection might have developed on the top of that. Do steam inhalation and take some antihistamine. If you don't have fever, then you can wait to see your doctor in a few days.
Pollen. this time of year it may be from high pollen count and allergies. Try an antihistamine like Claritin (loratadine) over the counter. Yellow stuff usually means it is not a bacterial infection. Stay on the Claritin (loratadine) for one week. Also Check your temperature and no fevers. .