My 6-month-old is getting really cranky in the past few feeks. At times, he would cry all of a sudden while asleep. Is this just a phase?

This happens every so often with my daughter also (though not as often now that she's past 1). I chalked it up to teething (or bad dreams?) but usually if it's difficult for them to go back to sleep, they give you clues and you just go through the process of elimination. Last night my daughter had a hard time falling back asleep and was scratching at her shirt. I thought it was because there was some water spilled on it (so I inserted a towel). Later on I realized it was because the bumps on her skin were itchy. Massaged lotion onto the rough patches and she fell right back asleep.

I observed It always happens when my son is too much of play and laugh before he sleeps. he wakes up in the middle of the night crying and it was hard for me to calm him..

Might be a sign of teething? I remember back then when my kids were teething, it was really hard for them to sleep properly in the night. Try looking for other signs

Honestly it is probably he is just teething another sign to look for to tell if he is teething is if he is drooling a lot

I have the same problem too. My 4 month old baby now is getting really cranky and always wake up in the middle of the night crying,

It could just be colic, but if you want a peace of mind, maybe try consulting with a doctor.

maybe he is too tired.