Hey danni,
just a few suggestions,
Mason is at wonder week 5 so his behaviour is perfectly normal. Have you tried giving him a warm bath and massage or my other suggestion would be to just carry him in a sling if you have one. I know with Hendy when he went through the wonder weeks i wouldnt fight him id just carry him in the bjorn as it meant he was content and that meant that i wasnt stressed. I even would have a cat nap on the couch with him in the sling on my chest. HTH