Hello kuldeep Singh,
Welcome to the Microsoft Q&A and thank you for posting your questions here.
I understand that you upgraded your SQL DB from General Purpose Tier to Hyperscale and price increases unexpectedly after upgrading to the Hyperscale tier.
Hyperscale pricing can vary based on several factors, including the number of vCores, storage used, and any high availability replicas which was not put into consideration in your price analysis at initial stage - https://azure.microsoft.com/en-us/pricing/details/azure-sql-database/single
Also, Microsoft recently announced changes to Hyperscale pricing, which might affect your costs - https://techcommunity.microsoft.com/blog/azuresqlblog/azure-sql-database-hyperscale-%E2%80%93-lower-simplified-pricing/3982209
If the price changes are unbearable, I recommend reaching out to Azure Support via your portal for a detailed review of your billing and to ensure there are no unexpected charges.
I hope this is helpful! Do not hesitate to let me know if you have any other questions.
Please don't forget to close up the thread here by upvoting and accept it as an answer if it is helpful.