Contact causing a painful cry at the treatment centre (5)
I believe the answer is:
touch
'contact' is the definition.
(touch is a kind of contact)
'painful cry at the treatment centre' is the wordplay.
'painful cry' becomes 'ouch' (I've seen this in another clue).
'at' means one lot of letters go next to another (I've seen this in other clues).
'centre' means to look at the middle letters.
The centre of 'treatment' is 't'.
'ouch' after 't' is 'TOUCH'.
'causing a' acts as a link.
(Other definitions for touch that I've seen before include "Compete with" , "spot" , "Side beyond playing area" , "small quantity" , "Graze" .)