A. It depends on a few different factors. Your current fitness level and the intensity/type of workout will affect the muscle soreness duration. When you perform strength training exercises, you actually break down the muscle tissue and cause inflammation within the muscle strands. If you are a conditioned fitness enthusiast, your body will adapt more quickly and be able to rebuilt the tissue that has received trauma during your bout of exercise. If you are deconditioned, it may take a little longer for the body to repair the tissue that was broken down during exercise. This soreness is often referred to as Delayed Onset Muscle Soreness (DOMS) . Generally most people will experience localized muscle soreness in the muscles worked for 1-3 days.
Another factor which will determine the duration of DOMS is nutrient intake. If after your workouts, you fuel your body with the proper balance of macro and micronutrients you will provide the body with the building blocks and tools to repair the muscles more efficiently. Muscles are comprised of approximately 70-80% water, 20% protein and 5% carbon and other matter. Maintaining enough proteins, fats and carbohydrates to rebuild the muscle tissue will allow the body to heal more efficiently and reduce the healing time as well. Proper hydration will also play a huge role in the healing process.
Massage or rolling the muscle tissue with a foam roller will help minimized down time as well. Stretching the muscles after your workout will help as well. It will increase blood flow to the muscles which carry oxygen and vital nutrients for healing. Another trick of the trade is to do a light workout using the same muscle group(s) that are sore within the next few days. This will also increase blood flow to the muscle and increase healing time.
So again, to answer the question, most muscles soreness should last 1-3 days and should be localized to the muscles that have been worked. It should be a dull consistent pain. If you experience throbbing or sharp shooting pain or the pain is in another region than was exercised, you may have caused a strain or injury. If the pain becomes progressively worse or lasts longer than week, you may have strained or even torn a muscle, or ligament. If you feel pain in a joint, this is not a desired result from exercise. If you experience these conditions or you have any doubt, it may be wise to have it checked by your physician.