I feel a little achey now, but that's pretty normal, swim or not. My neck, mainly.
I ordered a swiMP3, a cool little contraption that plays mp3 files in the water. It uses the bones in your head to transmit the sound, and apparently works very well - but just in case there's an issue I got a one-year warranty, free, from the seller. I told Mary I plan to take out books-on-CD from the library and record them and listen to them while I swim. She thinks books will be too distracting. I said "All I have to do is count, and I mess up on that even now." But added that if the books are a problem I will just listen to music.
I am not a big fan of distracting myself from what I am doing. I tend to lean toward the "be the pain" rather than "distract yourself from the pain" - I think in terms of the Bradley as opposed to Lamaze childbirth methods (I did in fact use Lamaze; I didn't know about Bradley until later, and hell, it was fine, it worked all right for me). I don't bring my "sounds" with me when I hike because I want to be there fully, in the present, on the hill, feeling the wind, hearing the birds and the rustle of the grasses and the trees. HOWEVER. This lap swimming thing is so artificial that it is difficult indeed to get through it without distraction. If I were a good swimmer or if I were learning a new stroke I wouldn't consider any kind of distraction. But when all I am doing is my time in the pool, and when I have a stroke that gets me through it reasonably well, what the heck, I'll take the distraction. Similarly on exercise bikes or any of the other equipment in the gym - those things are so deadly boring to me mainly because they are simply what they are, and no more.
I also suspect taht I might be able to talk myself into a greater number of laps if I am involved in a book. I am looking forward to getting my new toy.