Is it permissible to recite Surahs and do Dhikr whilst doing other things such as household chores, doing your hair, or being on the phone? Does it affect the reward?
Bismihi ta'ala
In fact, it is a very good thing. Although you might think that you are distracted, or your mind is somewhere else, but getting used to remembering Almighty God frequently is a wonderful quality.
It will minimise the chance of committing sin, and also keeping you vigilant and alert. Gradually, while multi-tasking, you will be able to master your concentration, and it will all have positive impact as well.
With prayers for your success.