Why are my SMS messages being sent automatically? When I start composing an SMS message on my Samsung Galaxy S2, if I pause for a couple of minutes  the SMS gets sent automatically, even though the message hasn't been finished (and I haven't hit the "send" button). Is there some way I can stop this happening, please?
You could start off by checking if this is a problem with the Messaging app itself. Install an alternative SMS app (I use GO SMS Pro myself).

If all's fine with the alternative app, and you don't mind using it (they're much more powerful anyway), problem solved. Otherwise, you could try out what patchie is suggesting.