Hi, I had gone through your question and understand your concerns. Do you have any medical history? For an immediate action, apply an ice or an icepack, rest is required.See your doctor immediately if your symptoms aren t relieved by icing and rest. Climbing stairs or ladders may cause leg pain. Reason could be a calf strain which is an injury to the muscles in the calf area (the back of the lower leg below the knee). According to the information, a “popping” sound may be heard or felt when the injury occurs (grade 3 calf strain). Stiffness,sharp pain,swelling,weakness in the lower leg muscles could be the symptoms. Few more contributing factors could be poor calf flexibility,ankle joint stiffness,inappropriate or excessive training or activity,poor biomechanics,poor foot posture (especially flat feet),decreased fitness,neural tightness,fatigue,poor balance. I would suggest you to follow up with the physiotherapy in which the treatment will include soft tissue massage,the use of heel wedges,achilles tendon or calf taping,stretches,joint mobilization etc. It will recover fast. Hope this answers your question. If you have additional questions or follow up questions then please do not hesitate in writing to us. I will be happy to answer your questions.