Headache may be due to severe gastritis...take esmoprezole 20 mg before food for 30 days twice daily....do quadriceps strengthening exercises for knee pain with OTC pain killers...try eating several small meals instead of three large ones whenever you can...Avoid foods that irritate your stomach, especially those that are spicy, acidic, fried or fatty... avoid coffee,tea etc... Avoid Stress as it may make your gastritis symptoms worse..Consult physician and orthopedic surgeon they will do the needful.