B.C.
I might take him to an Ear Nose Throat doctor to really check his ears out.
I'm wondering if it's a problem that only happens when he's crying.
Tears drain to nose and throat and if a duct is blocked he might be getting a pressure buildup but only at certain times.
There's a lot of things happening around that age.
More teeth are coming in, tonsils and adenoids can start causing trouble, etc.
I'd just feel better if an ENT looked everything over.
At 2 and 3 yrs old they grow in leaps and bounds and it's not always a smooth ride.
Nightmares can start up - fear of monsters under their bed, etc.
Separation anxiety can get worse.
Our son skipped terrible twos but made up for it with terrible threes.
It all seemed to get better when he turned 4 (and his tonsils and adenoids came out right after his 4th birthday).