To diagnose a problem with the port, try using a different battery and cord for a while. Damaged Power Cord. The power cord is a wire inside a plastic sheath, and the wire can break with or without damage to the sheath. If the power goes on and off as the cord is moved or bent, the wire is likely broken.
You can work out if you're sore. Don't exercise the same muscle groups that are hurting. Do legs one day and exercise your upper body the next. By doing so, you'll still be able to get exercise and allow your lower body to recover and rebuild.
1 If you can lift whatever weight you are using 20 times, it is too light. If you can't lift it 10 times it is too heavy. (unless you are into power lifting or bodybuilding)  If you are new to weight lifting, you should be sore the day after working out.