There is a pain in my right leg. the muscles were very tight especially around the fibula. is there any way to relieve the pain and relax the muscles?

Of course: Did you hurt your leg in any way? Excessive use of a group of muscles can cause them to get fatigued and need to be nursed back to normal with rest and some OTC anti inflammatory agents like Ibuprofen etc. Muscle relaxants are prescription drugs and should be reserved to treat those cases that have been assessed by doctors for a proper diagnosis.

Pain near knee: Are you saying you have pain around your knee? Strengthening your Quadriceps can be helpful. Squats, knee bends can be of help

Leg pain: Not sure if this was due to strenuous activity or if it just happened spontaneously. If you are not allergic, you can take ibuprofen 400 mg every 8 hours with food. You may try massaging the muscle, use a foam roller, or apply warm moist heat.