He is only 3 months old, and with pneumonia... there SHOULD be a follow-up Doctor appointment, since he got discharged from the hospital.
If not, make an appointment.
Since he is so young and because he had/has pneumonia... don't take things willy-nilly... and follow Doctor's orders. You don't want to just experiment with things, hoping it will help or lessen his discomfort. He is too young... and pneumonia is serious.
It takes time to fully recover from. More than just 2 days.
If you feel the Albuterol is NOT working... or anymore, you MUST tell the Doctor. They don't know the condition of your baby or the effects of the medicine, unless you tell them. If you don't tell them, they will assume your baby is fine.
Albuterol is fine... that is what I was given once for the same reason. But I also have asthma, and take it when I need too. I even had to take it when I was pregnant with my 2nd child. Its fine... Albuterol is a muscle relaxant for the bronchial airways.... to help with breathing etc.
ASK YOUR PEDIATRICIAN and take him in for a follow up appointment... if his symptoms changes or returns or he gets a fever or anything different... you need to have him looked at.
AND if he is worse, take him to the ER.
AND make sure he is hydrated... feeding him ON DEMAND, no matter how often, 24/7.
All the best,
Susan