I have a problem

[RastaKyle]

For a while now I wake up sneezing and having to blow my nose constantly. When I leave my house the sneezing and blowing my nose lessens. Also, I've been doing a lot of grunting a lot because i have a feeling of phlegm in my chest. I have been burping a lot more often that I have been taking a medication to stop my burping. After eat I do feel regurgitation. Could this be the reason of the feeling of phlegm in my chest?

[eczemainvestigator]

I think your sickness is related to something wrong you have eaten.

[RubyWitch]

If you don't have a cold, I'm guessing the sneezing and nose blowing are perhaps an allergy to something in your house. Since it wakes you up at night, I'd focus on your pillow, your blankets or possibly your laundry soap.
Animals sleeping on your bed could be another cause. An open window that would allow pollen to enter your bedroom may be the culprit.
Allergies can start at any time in our lives, so if you say you've never been allergic before, doesn't mean you can't be now.

In a prone position, our sinuses drain, often leaving us with a sore throat and  phlegm that we cough up.

That you are feeling some regurgitation after eating and you've noticed that you are belching more could be an indication of a reflux problem.

I don't think the problems you've mentioned are related, but I would suggest you see a doctor.
Peace
Greenlydia