Question: I'm currently playing a piece which requires big stretches of large intervals across the keyboard. It slightly hurts when I do so, and I am wondering if I should continue to practise like this.

[![Bartok Suite op14 - Allegretto](https://i.stack.imgur.com/6cfvl.png)](https://i.stack.imgur.com/6cfvl.png)

My piano teacher suggests fingerings with a combination of 3 1 and 2 1 in the L.H.

Answer: 
Don't persist in doing anything that hurts. 

As commented, if you show us the passage in question we might be able to suggest a strategy.
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> It slightly hurts when I do so
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Huge cue! You should never ever insist with something that hurts and that could damage you in any way. If somebody recommends some kind of exercise, but when you do it, it hurts, the exercise just isn't right, or you are not doing it right, or the exercise doesn't work for you. Either way, you should never go through pain to achieve anything.

So, shortly:

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> I am wondering if I should continue to practise like this.
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No.