If you can make it to Yabe (about 10 minutes out of Machida on the JR Yokohama line) I can recommend a master massager.
He speaks English well enough, and it is quite cheap.
I consider myself to be his 'bionic man', as he rebuilds me every time I screw myself up with too much cycling, gardening or load-lifting.
In my years in Japan I have had a lot of back problems (all stemming from the time I tired to lift an oven ...), and no amount of visits to 'Western' doctors helped me. I found 'guru' type Japanese massage-men, usually in their late-40's, who were very inscrutable - but were truly masters of their art.
Sadly I have lost the information about the chaps I used to see in Saitama and Ota-ku, but this guy in Yabe is a genius.
Expect pain beyond your wildest imaginings though ... especially on your feet.