Due to pain in legs, can we short Isha prayer, if yes then how??

If one suffers from pain in his legs and is unable or experiences difficulty in standing, he may perform his Salaah sitting.

The method of doing this is that he seat himself either on a chair or in tashahhud position (or as close as possible) on the ground and make his rukoo' and sajdah by indication. His sajdah, in this case should be lower than his rukoo'. If he is seated on the ground, he can make sajdah normally.

and Allah Ta'ala Knows Best

Mufti Bilaal Cassim
FATWA DEPT.