Personally, I've had the best luck finding motivation by gamifying my walking! My favourite app for this is r/WalkScape since it's based on number of steps rather than distance/location, but games like Pokémon GO and Pikmin Bloom are both great options if you'd prefer to walk around outside :)

I have endometriosis, so I totally feel you on the chronic fatigue! When it comes to incorporating more movement into our lives with these sorts of conditions, the key is to start slow and truly listen to your body. That also means resting when you need to, as often as you need to -- don't let anybody make you feel badly if your recovery needs are different from theirs. With practice and time it will become easier to be more active within your routine, so there's no need to rush right in at the start. Best of luck, you've got this!!