Hi... Your knee pain is because of your tight butt muscles pulling up the non contractile illio tibial band... the band is attached to the outer side of your knee slightly below the knee.... When this gets tight your calf muscle will get tighter too as it induced spasm due to its attachment...so every time you bend and extend your knee you feel stiff and very painful knee... when you walk on this stiff knee it demands a lot of strength...and gets fatugyeceasily onvtop of it you are in antibiotics to combat pneumonial infection lose micronutrients resulting in cramps... I recommend you to.. Increase your water intake.. Take good diet... Apply ice frequently in the outer asect if your knee...15 mins for ever 2 hours.. Keep it wrapped in compression bandage... If somebody is there for your help ask them to knead in your calf especially over the outer calf and outer side of thigh especially lower part near the thigh..it will be tender and follow this up with icing.... keep your legs flexible..keep stretching your calf... Hamstrings..and your gluteus.. frequently... once you are out of pneumonia then you can begin with stability exercises for your gluteus and knee..this will prevent the problem. in future.. Hope this is helpful for you... Kindly revert back in case you need further clarification .