my son when he was in reception/year 1 sort of age used to chew his fingers. when we aske him why he said it was because they were numb and it helped him be able to feel them.
I seem to remember we took him to the Doctor but they didn't think it was an issue.
hes now 11 and saying when he wakes up he has to clench his fists to get his hands moving. like they wont move or are numb. this is worrying as I googled it and it sounds like a nerve issue. my family does have a history of rheumatoid type diseases.
he also has said hes had this for some time.
more recently he also complains of pain in his arm joints. I wonder could it just be hes growing faster than the nerve connections?