Yes a warm bath is always good for aching muscles.
If you have sore muscles the warm bath can help relax those aching muscles and help alleviate the pain.
Whenever I have aching muscles I like to relax in a warm bath for 30 minutes to an hour and the soreness and aching muscles just melts away.
A warm bath is very relaxing and even taking a hot shower and letting the hot shower water run on your back muscles can help relieve aching muscles and help relieve back pain.
Sometimes I prefer to take a nice warm bath and relax and other times I take a nice hot shower and the hot shower also gets rid of the aching muscles as well as the back pain.
I also recommend taking some pain medicine to help alleviate the pain and if the pain still persists you should also have a massage done on your muscles as that too helps relax the muscles and helps with the aches and pains that your muscles can have.