oh hun... i had pneumonia in feb this year and it sucked soooo much. that pressure is the worst.
try to sit in some steam or have a big pot of hot water with a towel over your head.
did the dr give you some steroids to build your lungs back up? they do help.
i found sitting up in bed at night much better because when i lay down i felt stuff in my chest move and loosen and made me cough more.
try to take deep breathes again and pretend you are blowing up a balloon to build your lung capacity back up.
not sure what else i did but i hope something i have suggested helps.
also when you finish your antibiotics(but only when you are finished them not during) take some innerhealth plus to get your good stomach bacteria back.