Hand Pain from using the iPhone

For several years I have noticed hand pain when holding the iPhone.  I always just assumed that it was caused by phone radiation heating the hand nerves or inducing a small voltage difference across the crucial membranes therein.  Tonight I performed a quick search on the subject and found a few entries claiming that it was a type of repetitive strain injury (RSI) or carpal tunnel syndrome.  I also saw various comments and replies attributing this phenomenon to "texter's thumb".
Personally I don't believe these.  There is no doubt that phone radiation can heat things, like my thenar muscle.  If I had time I would design a double blind placebo controlled study to test my hypothesis.  I think this would be a good school science project.  There is no evidence base for an opinion either way and if there was evidence (in the secret Apple archives) they would be crazy to release it.  Meantime, I'll keep an eye on this subject - maybe with a Google Alerts search as shown in this link which searches for "hand pain from radiation of iPhone".

Am I concerned? Not a bit.  We know that phones can heat things in their immediate proximity.  If they caused tumours we would have a massive outbreak of brain tumours amongst people like myself who have used a cellphone for 20 years.  It isn't happening.
The lesson from this is that plenty of content on the internet is useless, or just plain wrong.  This might include my comments here!