4 times a week squashing seems "a lot"
Maybe I am doing too much too soon, I never really considered 4 times a week to be too often but maybe it is.
Squash is brutal... almost gladiatorial.. I love it

How heavy are you now?
Whats your BF??
Are you getting enough fish oil in your diet? If not consider tablets.
Is there a conection between the intensity of the game and the soreness the next day?
Or the length of your warm up/warm down?
Are you warming down?
I agree squash is great!
I went from 197lbs at 25+% BF to about 145 at 9% BF now, it was quite quick, too quick perhaps. There doesn't seem to be any connection between the soreness and intensity, my partners and I are all about the same standard (rubbish basically) and sometimes even after brutal games there is no pain and vice versa. I get through alot of fish and also take omega 3 etc daily.
Warm up is usually a good 10/15 mins but I'll be honest, (and I'll probably get flamed for this) warm down is virtually non-existent. The place where I play has a jacuzzi and I'm usually looking to get into the shower and jump in there as quickly as possible after playing lol.
I will look into some good warm down routines!