My 4 day old baby only settles when he is breast feeding, other than that he crys and wont sleep, tried many things, nothing works. Plz help!

Soothing. Newborns can be very demanding. I often refer to the 5 s's (swaddling, sucking, swinging, shushing, side-lying). This approach is related in an excellent book by a pediatrician from ca, entitled "the happiest baby on the block." patience and consistency are the most important ingredients. Good luck.
Teach baby to rest. My moms find it helpful to set patterns:days- feed while waking/ change/ play until tired and then place in the crib for a 2 hr rest.No more than 2hr nap on days or they flip their day night. At night the rest period is extended until they wake, then feed, change/to bed. Mom's who settle their baby feeding will have 400% more sleep pbs for the first 3-4 years.