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As you have explained in your query all your problems can be explained because of forceful vomiting
The vigrous vomiting you experienced might have led to muscle spasm of your back which could be the cause of your back pain
Muscle spasm can be releived by some muscle relxant medicine/counterirritant application and some physio.
For throat pain you have already explained the cause the gastric juices.
Hope your query is answered with your satisfaction.