Right brake handle stuck

[urforgetfulbird]

To anyone out there who may have some advice, my mountain bike handle is stuck.
I checked the brake tension and it seemed to be o.k.
Is there anything I can do to fix it without taking it in?
Any help would be greatly appreciated.
Thanks

[cyclerUK]

Remove the cable and housing from the brake as this could be seized.
This will also show if it's the brake lever.