Hello,
It is awesome that you are working out after being sedantary, that is not an easy adjustment! Dehydration may be to blame for sore muscles (not to disregard the depletion of muscle fuels and lactic acid accumulation). Be sure that you are hydrating appropriately and maybe try eating a banana before exercising (this will ensure that you are getting the nutriets that your muscles require). You could just be expericing a work-out hangover, a hot bath will loosen and relax muscles, especially if you add lavender oil. OK one more thing: Comfrey relieves pain, swelling, and inflammation. Arnica may work, too.
I hope this helps!