difficulty breathing

hi mga mommies... it's may first time to experience ung short breathing and ung paramg mabigat na chest ..this happens everytime i walk few steps or kahit movement lang around the house... wala naman akong asthma attack as of this time... im so uncomfortable with my chest while breathing... have you experienced the same? im on my second pregnancy and on my 3rd mon. now.. is this normal? worried mom here....