Certainly I've had some motivation issues while working from home every day for 8 weeks. Thing is, talking to my colleagues and my manager, we are all feeling the same. If your normal work is at "the office" and home does not normally = work, being at home all the time makes you feel like you should not be working.
I see two sides to the coin; Im a loyal/honest person, so if Im taking the money, I need to show something for it, but on the other hand Im naturally happy to chill out, sit back and relax. So the motivation comes in waves.
A big issue for me is when projects or tasks get halted, picking up half finished work I find extremely dull and hard to motivate myself for. When something is new, you can focus time and energy into it, if that initial energy bubble is allowed to dissipate because there is a big time-gap, then re-engaging that energy is very hard. I suppose new things excite me, but like a cold half-eaten dinner, appetite is easily lost. So for me, start and finish is important, don't let things languish.
Finally, the biggest single motivational tool I have, is a good nights sleep! I don't sleep long/well a fair amount of the time, and those days even small tasks can seem insurmountable; a good sleep later and I have achieved a huge amount in next to no time, and the motivation came so easy. I'm learning not to try and do those "hard" tasks on tired days, if at all possible, leave to a day when you feel great, and as if by magic I can "just do it".
RE: mental health lack of motivation – and how to overcome it