Chest Fullness And Tightness - Bronchitis?

Could be bronchitis, because you will feel very tight in the chest. Normally it would be accompanied by a pretty painful cough and phlegm. It could also be pneumonia, since you aren't actually coughing anything up. Sometimes pneumonia congestion can be so deep that it is impossible to actually cough it up and it tears up your lungs instead.

It is possible that your post nasal drip is just going straight to your lungs and filling them, or you could have a lung infection that isn't sinus related, or both.

You should have a doctor to check you out to make sure you don't have either of these conditions. Pneumonia can be swift and deadly.

Thank you, I'm feeling the same way and just took my temperature it's around 95 or 96. Is that typical?
The pharmacy said to take a mucus pill with a cough stopper. I'm worried that it might make it worse, the cough depressent. What do you think?

You should take something like Mucinex or Robitussin (both should contain Guifenissen and only that), but not a cough suppressant. Guifenissen helps make your secretions thinner to clear the buildup. Using a cough suppressant will clog your system and you could end up with an infection more easily. Your temp could be low if you are taking fever reducers like Tylenol, or if you are female, this is the normal fluctuation of temps due to hormonal changes.