Sometimes if happens that the moist beds are heavens for mites, also if you have fur or woolen blankets, that also could cause itching.
The best way is to expose
the bed to sunlight, but as you seems to be from UK,
the bright
sun may be rarely observed, therefore go for good pest control.
Secondly, some time it may be just your Psycho, my Son who is 12 year old, when he wakes up in bed, just keep on scratching his sholder, arms, and armpits, even though afterwards he never scratches.