Hi wecome to HCM I have gone thru your query regarding severe back pain after taking yellow fever vaccination . I can understand your concern . Dear , the symptoms you have described may be side effects of the yellow fever vaccination . Up to one in every three people experience mild side effects after having the yellow fever vaccine, such as: a headache , a mild fever muscle pain, joint pain, body aches; or pain, tenderness, swelling, or a lump soreness at the injection site . Reactions at the injection site usually occur one to five days after being vaccinated. The other side effects may last for up to two weeks. heat pad I suggest you to carry on regime till two weeks.After that side effects may go by itself. Over medication can make things bad to worse . Your pain also can be due to imbalance of (Vayu Tatv gas , a side effect of vaccine in your body , which is responsible for your pains and inflammation . Proper regular physical activity , walk ,meditation ,pranyam - deep breathing ,Yoga - back bending exerises to relieve your back pain , to boost your blood circulation and detox your system under guidance of trained guide and balanced diet, including ,all essential nutrients as fiber ,vitamins,minrals and antioxidants Ginger , Garlic , Amla , Aloe vera , nuts , Turmeric powder a spoon in a cup of hot milk at bed time ,Cocconut water ,all in natural form and intake of lot of fluide ,help, eradicate Vayu Tatv ( gas) alley pains and inflammation and give resistance from diseases . It is advisale to consult your doctor before following any regime Hope this helps solves your query .Take care , All the best . Don t hesitate to get back if have any further query