What is it about NTs ...

I’d generally be wary of generalising (about any topic) from “this is overwhelming for me as an autistic person” to “NTs seem to need it”.

In this case, some autistic people actively seek out loud, rhythmic sounds as part of sensory-seeking, and could actually enjoy that aspect of your shopping centre experience.

Autism-related sensory processing can differ in more than one direction (hyper- or hypo-sensitive), and it can also be mixed and context-dependent (for example, enjoying loud music, but not other loud sounds). 

Also, plenty of neurotypical and, more broadly, allistic (not autistic) people also dislike loud music in shops.

Noise aside, shopping centres can, of course, still be very difficult for lots of us for other reasons, too - like the examples here:

NAS - Autism and sensory processing 

Practically, you could try headphones or earplugs to help, but perhaps you could also consider asking whether the shopping centre runs - or would be willing to trial - quiet sessions?

For example, the Metrocentre in Gateshead offers quiet sessions twice a week with adjustments including dimmed lighting and reduced noise from in-store music and announcements:

Metrocentre - quiet hours

I quite like loud music when I want to listen to music, 

But not when trying ti concentrate on making decisions on things  need to spend money on. To me they are different activities 

I quite like loud music when I want to listen to music, 

But not when trying ti concentrate on making decisions on things  need to spend money on. To me they are different activities