I am pregnant & recently noticed a lump under my left breast that is quite painful. do u know what it is?

Many do get those: At your age, breast cancer is not very common and sore breast lump during pregancy likely =blocked milk gland or cyst. If the lump feels a bit squishy, it is probably a "clogged milk gland" which is very common. It is anxiety-provoking for a lady to feel a lump in her breast, but i would not worry too much in your case--see your doc for an evalation. Congrats on the pregnancy and good luck.