What Causes Severe Vomiting In An Infant?

My little girl is 17 months old she is constantly vomiting she's bringing up milk mainly that comes out in a cottage cheese substance she has had bronchiolitis previously and seems to have always got a cold and cough on and off which is sometimes the cause because of the coughing but she has trouble with lumpy foods and finger foods which subsequently end up causing her to bring stuff up she has to have foods which are very runny or very soft or tiny pieces just so I can get some food in her without her being sick straight after?