Hi mama! Ang dami ng saliva at milk discharge ay normal sa ganyang edad, pero yung pagiging resistant sa burping at body stiffening when crying sounds like something worth checking with your pedia talaga, baka may reflux or discomfort siya na hindi pa natin na-address. Try gentler burping positions muna (like sa shoulder mo pero very light pats lang, or lay him on his side habang sitting) at observe kung may pattern siya when it happens, after feeding ba talaga or anytime? That info helps your doctor understand better, kaya i-note mo na rin. Hang in there, mama, first few weeks are the trickiest!