No desire to do things sounds like anhedonia, a common symptom of depressive disorders.

If you have motivation to do things but it's just weirdly hard to make yourself do it, that's more initiation impairment AKA initiation deficit. (Psychiatry doesn't give this much attention; I only found out the name through resources on traumatic brain injury.) I have this problem, it really sucks.

Those are just traits/symptoms, not diagnostic labels. They can each be caused by multiple conditions. Initiation impairment seems common with ADHD and, to a lesser extent, ASD.