If a young infant spends a lot of time crying and sleeps poorly he should be checked by his pediatrician to be sure he isn't ill. Infants who have many episodes of crying may have colic . Such infants may require a great deal of soothing, but this stage rarely extends beyond 3 to 4 months. If your infant cries a great deal you might consider putting a ticking clock in his room to simulate the rhythmic sound of your heart beat since he spent 9 months in the womb hearing and feeling that rhythm. You might add some white noise to the room to block out other stimulation.
White noise can be as simple as a radio tuned to no station so there is only static.
Or you can get a white noise generator that provides a variety of soothing sounds. Nature's Cradle by Infant Advantage also lulls a baby to sleep with sound and motion. By 4 months of age, most infants should be able to sleep through the night without feedings. Since infants derive such great comfort from feeding, it should come as no surprise that a feeding can soothe a crying infant even if he isn't hungry. Some infants become dependent on having feedings to soothe themselves and put themselves to sleep.