It's painful to pick up when hot (5-7)
I believe the answer is:
heart-rending
'it's painful' is the definition.
(heart-rending can mean upsetting or distressing)
'pick up when hot' is the wordplay.
'pick up' becomes 'hear' (hearing is a kind of picking up).
'when hot' becomes 'trending' (both can mean fashionable. I am not sure about the 'when' bit.).
'hear'+'trending'='HEART-RENDING'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for heart-rending that I've seen before include "Greatly distressing" , "Poignant" , "moving" , "Causing great sadness or distress" , "Agonisingly sad" .)