Hi welcome to Health care magic forum. As you have described if the difference between the 2 legs is 4cm you can't walk with out support. Probably you have developed an illusion that it is bothering, or your muscles became week with the age. What ever the problem is don't worry, consult an orthopedic surgeon for diagnosis and treatment. You can have relief with shoes , the heal of one shoe is high and inside to lengthen the effected leg.
Besides i advise you some diet recomendations as take more of green leafy vegetables , pulses, sprouts, milk, egg, meat, dry fruits to increase blooc, general health apains and muscle weakness
. nd vigour of the leg as well.
Avoid taking potato, other tubers, tomato, coconut, sea foods, to avoid pains and muscle weak ness. Wishing for a quick recovery and thanks for calling.