Since you seem to be working as a software engineer at the grassroots level and are considered a technical person, you may be covered under the definition of a workman of the ID Act. Forced resignation is unlawful termination. You need not resign; instead, send a registered protest letter to the MD enclosing an application for the grant of leave on medical grounds along with the original medical certificate from a doctor, preferably from a civil hospital, advising bed rest. State that you are being unlawfully pressured by HR to resign solely due to an accident you had on a specific date. Such unfortunate accidents can happen to anyone, and you expected assistance from the company. Await a response. Read the thread titled "Forced to resign due to my hip fracture."
Thanks,
Sushil