Suggest Remedy For Severe Chest Congestion And Cough

my 2 months baby got her needle friday past and now she has a cold on her chest where as when she cough i could hear the cold she try to bring it up but she can her chest gets tight and she cry alot because she cannot brinb the cold up of her chest what can i give her for her to bring the cold of her chest so where she cannot be getting chock