Chest tightness in early pregnancy is a common cause of heartburn, indigestion, stress and changes in the body. Heartburn or acid reflux is a fairly common condition during pregnancy, and if it is caused by this condition, chest tightness is most severe and noticeable after a pregnant woman has eaten. Heartburn may cause the patient to have a burning or warming sensation in the chest accompanied by pain, and in severe cases it may lead to throat inflammation. Stress refers to excessive worrying during pregnancy. Too much worrying can also cause a pregnant woman to have chest tightness, as all the body functions are adjusting and even growing throughout pregnancy, some of these changes can also cause chest tightness in pregnant women. For example, the swelling of the uterus and the enlargement of the breasts will exert some pressure on the diaphragm of the pregnant woman, which will lead to the appearance of chest tightness.