Your baby might be suffering from colic. It is common in infants below 3 months. Colic has many reasons like gas, indigestion. You can try remedies like tummy massage, pacifier, carrying your baby on your shoulder and patting him. Introduce pacifier if he wants something to suck. it relieves colic too. If nothing works and if your baby cries excessively consult a paediatrician and it's good to avoid certain foods which may give gas to your baby..