I invested in a shoulder massager a couple of years ago and I'd forgotten just how good it felt!
I've just changed the batteries in it and put it over my shoulders, set it going and OMG! It's so totally awesome!
It only takes 2 AA batteries but it feels incredible!
I think it was under £20 too which is even better!
I've got no idea what knots are, but this is getting rid of them and relaxing me at the same time... the only negative is how noisy it is but for less than £20 and running off batteries that is so totally forgivable in my eyes!
If you want a basic neck and shoulder massager, get thee a Homedics Snuggly Bear massager and you won't go far wrong! They do massaging slipper boots too, but I haven't tried those... yet! So totally awesome!