Dear Dharmesh,
Try increasing amount of water. Make sure its atleast 5ml for every one vial of desferal and transfuse it not less than 8hours. Even then if you experience problem 'itching / rashes' on the injection site then you can increase water more than 5ml for every injection.
Secondly, I think that its not because of desferal that you are experiencing side effects but because of Asunra. Why I am saying this is because you have not been taking desferal for long time, since this is reflected in your iron levels, and even you are not taking high doses. Desferal toxicity increases when ferritin levels are very low and desferal starts disturbing you or when you are on desferal for a very prolonged time.
So far, nearly every thal I met had not seen other side effects of desferal except 'itching/rashes/lumps' on injection site.
I think you should check again, whether it is desferal or asunra causing problems.
One more experience I would like to share. In 2002/2003 I had high iron levels. Sure around 10,000. I used desferal only 24/7 and within a month ferritin was 5,000 and next month it was 2,500. Dont undermine the power of desferal, if taken correctly will yield excellent results.
Since your iron levels are very high and given your chest pains. I think you should not compromise desferal at all.
This is my suggestion. In the end, you are the boss !