My 7 month old DS has suddenly decided he doesn't want solid food and only wants breast milk. He has been feeding so well for a month and now screams, clamps his mouth shut and shakes his head. I don't get stressed or force him but try again after a minute or two, but still the same. He has had a cold and a bit of a cough lately. What on earth is this all about and does anyone know how I get my good little eater back on track?