Movement In The Left Side Of Ribs, Stomach Getting Bigger, Sore Breasts. Reason?

Been having like movement like on my left side in my ribs ,my stomach is getting bigger .For like three weeks my breast where so sore .But I m just finishing my periods that is not regular .I feel this movement all day long ,could it just be gas ,but its not like bubbles its more of like three feeling when someone rubs your hand .That is how it feels in my tummy .could you please help me .