Review the sentence:
Collapsed on the couch, Nick's relaxation was well earned after the
hard day of moving heavy furniture to his new apartment.
Collapsed on the couch, a participle phrase, comes right before relaxation, an illogical target. (Nick's, a possessive noun, functions as an adjective describing relaxation.) People, not relaxation, can rest on the furniture!
Before you continue, review the rules for misplaced and dangling modifiers.