7 month old breathing loudly / chest crackle for a month

[SpeckyB]

my 7-month old has sounded very chesty for 4 months. Her breathing is loud, she rasps and her breath crackles and rattles. I've been seen by the doctor a couple of times, and they say there is a lot of noise in her upper respiratory tract but her chest is clear. Antibiotics made no difference (amoxicillin) and neither does a cold air humidifier.

She sleeps ok and coughs rarely. In fact her coughs are getting weaker so the sound never clears. She is breast fed and so far refuses solids.

It does not seem to get better and it's been a month. This does not seem normal (she is my second). What can I do? I will go back to the doctor on Monday.

Thank you for reading.