Yes Adam ... I remember. I also recall where I encountered your Dad's van. A few years ago (ten or more?) now.
But regarding your "problem"; well, anything and everything is possible with technology, as we all know.
In order to advise further, we really need to know
where the "pain reports" are to be sent (and logged); and - what form should these reports take ... patient ID plus a time and date stamp? A 1 to 10 indication of severity?
Send to a Central Monitor (of the type found in ICU)? Send to the hospital paging system (do they still have them)? SMS to an individual nurse or doctor (and/or group of carers)?
If patients are mobile, then a fair variety of options come to mind. Depending upon how far they are likely to roam, you could be thinking in terms of radio! If they are wandering about "in the community" you could consider GPS!
In these sad times there is plenty of stuff on the web about Electronic Tagging.
The bottom line here is:- what's the design spec (detailed users requirements)?