I have a 4 year old American pit bull terrier that has been having really sore legs after exercising. It started a few months ago randomly and can last a day or two (sometimes longer depending on the intensity of the exercise) until her legs stop hurting. She is generally healthy otherwise and I am not sure how to help her.
My first thought is that you should contact your vet. I know that right now your vet probably has limited availability but he/she may be able to discuss over the phone and provide you with a course of action. Unless your dog is over-exercising, she should not be sore, especially not that long. Until you speak with your vet, I recommend that you limit your dog's activity - you can cut it down in increments to see how she does. I do know that some dogs will over-exert themselves and this can result in weakened muscles for a while (similar to how we get wobbly legs if we work out or run too hard). I know that one English Bulldog I care for gets sore when she over-plays so I need to monitor her and make her rest. I hope this helps! Good luck with your pup!