Hello in my opinion you should consult a good & professional physiotherapist and get yourself examined for the present problem. Also get do's and don'ts before, during and after heavy cardio exercises from the physiotherapist. If any querry you can have direct consultation with me on practo. Regards

You might have got a muscle pull. U needed to use ice pack at that time. If still pain is persistent u need to take rest and consult a skilled physiotherapist or an orthopedic doctor. If there is no swelling now use hot pack n take rest n use some pain gel. Don't do heavy cardio if pain is still there

Hello After heavy exercise muscles may have gone in fatigue . Drink lot of water Streches are very important before and after exercies. may apply heat pack if even after stretches the pain does not reduce For your thigh pain right now do quadrices stretch . Still if you dont get relief you may visit a physiotherapist who can assess you in person n guide you Also the warm up cool down phases both are imporant at gym !