iodine is an unobstructor. tightness in the shoulders is a clogged liver. heart racing is halogens bumping around in the heart due to halogen imbalance.
the heart stuff is temporary with continued, especially increased, daily doses. i have never heard of someone stopping the Iodine and the symptoms continuing. sounds like all you did was stir up the hornets, not chase them away.
as for the shoulders, a Liver Flush is indicated. some pathways were opened and then they hit a road block. its the liver.
the more severe the reaction, the more of an indicator that Iodine was sorely needed. it is recommended to do some cleansing and flushing before starting io-supps. the toxins have to have some place to go.