Re: crackling in lungs
Crackling means there is some fluid of some kind in the lung and usually this is caused by infection hence the antibiotics. Once you have had the antibiotics then go back to Dr and make sure the crackling has gone - if it hasn't then he will send you for a chest x ray to be sure its nothing.
I had flu once and it left me with a crackle on my lung for weeks but eventually cleared up itself.
The only time your Dr will be concerned is if it doens't got away after many weeks and maybe a course or two of antibiotics but an x ray would then tell them if it was anything or nothing.
Take the tablets sure you will be fine.