Cuilionn has it right, and so has Pete (shaw = thicket, grove). Chaumers = chambers, rooms, and the lad is either saying that the bright rooms are making him sad (to be leaving) or he's fed up with the brightness. Dinna ye think?? Weel, gin ye jalouse I'm no that richt i the heid or whit, jist tell me to gang wheech doon the cludgie, an I'll say nae mair.