My 6 month old is always crying and I don’t know why.. someone help

I know you guys aren’t doctors but I just need some advice, my son is 6 months he is very healthy but he’s constantly crying, if I’m not carrying him he will cry. He’s always fed, diaper is changed and everything and he’s been like this for months and I just can’t understand why he’s always crying and being fussy. For a minute I thought he may be teething, but he’s like this every single day and thru out the day, I don’t know if it’s because he’s very attached to me? Because he won’t let nobody else hold him but the moment I’m not holding him he will cry and won’t stop crying.. I just don’t understand why