Reasonably. It is reasonably safe. If you start having an increase in pain, this may suggest you are over using it and more rest may be needed; but if you are reasonably comfortable each day after you work out, it is not likely you are causing any problems.
No is not advisable. If you are healthy you need to exercise the whole body with moderation. Working out one group of muscles, causes muscle imbalance in the extremity, and causes disproportion in the extremity.