How to talk about pay

I have done work for my employer for a month now and there has been no talk of pay, is it reasonable to ask about my pay over text? this is a work from home job

No don't discuss anything like pay over a text message.
If you want to discuss anything about a pay rise then speak in person with your manager and see what happens but I doubt that you'll be getting it.
Most employers don't implement pay rises until April after negotiations with trade unions etc.

If you not getting paid the amount you were told them you are within your rights to ask them about this.

Hi, this sounds as if it could be a scam (this might be more likely if the person/organisation giving you work is based overseas and/or you have not got full contact details for them). Did you discuss either by phone or in writing what your terms and conditions would be, and was anything ever mentioned about money? If not, was there anything mentioned about this being a volunteer position ('for experience'). If you signed nothing and discussed nothing, it does sound odd. Usually, unless the job is definitely flagged as voluntary, regardless of whether it is part time and/or remote, there would have been an initial discussion about pay, although in many jobs for the first month, pay is not given - instead, it is backdated (so you don't actually lose out). However, if you are classed as a 'freelance' worker, you might not be paid for a while (you might need to chase). In any event, keep all evidence of the work you have done and any communications you have had and, if possible, always try to communicate via email so there is a chain of your discussions.

No I'm saying that I haven't been paid a penny for the work I have done, not a pay rise. This is a part time remote job with a company. They have asked me to do the next bit of work but I was thinking of not doing it until they give me my money or at least talk about it.