I know its a tough one isnt it when you need something and you are not covered those Xrays can be expensive,Is ther not one of those clinics near you sometimes they will help pay the cost if you come under the earnings rule, Perhaps you need to rest it more, maybe you are doing too much, if its swollen thre is the Possibility you Fractured it.Try Ibebrufen for the pain it is also an anti-inflamatory,3 weeks is not too long foe a nasty sprain but if the Pain continues you made need to go and get it looked at. Good Luck