Smelly scalp odour! I need help!?

My first question to you is this, you mentioned that this smell only started a few weeks ago, is it possible that in that time you have started using a new product in your hair routine? Cause that could possibly have an effect on your scalp and the smell... You may also want to purchase a more expensive brand of shampoo, as great as Herbal Essences smells, its really not a great shampoo for hair. Perhaps try an organic shampoo or something like that, I personally enjoy Bed Head products and have never noticed anything negative with that, however if that is too expensive perhaps try Tresemme. Greasy foods can cause your body to produce not nice smelling oils that come out through the pores on your skin (including your scalp). Also, try not applying to coconut oil on your roots, that could be "clogging" your pores, which isn't allowing your scalp to breathe properly, perhaps trapping your natural oils inside. I hope this was helpful in some way or another.