Hi.. Your left sided rib pain could be due to incoastal muscle sprain...with some costochindral joint involvement... Though you had adjustments in your spine you might need gentle mobilisation in the costochondral joint as well... Muscle spasm that got set in is the culprit responsible for your pain... stiffness...you will have relief only after this spasm gets releived otherwise it will be like a cycle....spasm causing pain leading tightness..again tightness and pain causing spasm... I recommend you to kindly do lot if icing on your painful area.. frequently...once in every 2 hours for 15 mins... Gently knead the area without much pressure to soothen the muscle... Don t do any movement forcefully as this might trigger that spasm again.. Take it easy for a while untill thus settle down..... Hope this is helpful for you... Kindly revert back in case you need any further clarification...