I am not sure about muscle ache. But when my daughter started walking first time. she did it 2 days , then she didn't walk for few days . after that she again started walking.
Yes, babies do get tired and have muscle aches too. You can help them massage too. Check out baby massages online
Okay thanks!◡̈
Babies do get muscle aches . You can try giving baby gentle massages with baby oil
Ya he can be tired
Dorothy