It’s important to establish the difference between the painful sensations that you may experience with working out. While there is pain present with strains, there is not necessarily a strain present with all pain. For example, pain can be soreness. Feeling sore after a day or two from your workout is perfectly normal. However, if you experience sharp pain or pain due to swelling from exercising, you may be dealing with a strain.
Muscle strains can be caused by 1) doing too much too soon, such as a drastic increase in the amount of weight being lifted or length of workout time, 2) insufficient warm up and stretch needed to loosen up tight muscles, 3) improper form and execution of exercises, or 4) muscle imbalances.
R.I.C.E. (rest, ice, compression, and elevation) can help alleviate the pain associated with muscle strains. Although, seeing a physician would be in your best interest. That way you can receive a proper evaluation and treat the injury accordingly.