Hello Irfan
If you have configured the ASA with subinterfaces on the interface connected to the switch, then of course, as you have confirmed, you should be able to ping the IP of the subinterface on the same VLAN as the device you are pinging from.
Now for traffic to be routed from one interface to another on an ASA (whether physical interfaces or subinterfaces), it takes into account the security level of these interfaces. I am assuming that each subinterface has the same security level. If that is the case, the default behavior of an ASA is to disallow traffic between such interfaces unless an ACL is present that allows it.
The problem may be there, but it also may be due to a default feature of the ASA that is configured not to respond to ICMP packets. In order to determine the specific problem, take a look at this post, as it will help you to troubleshoot the issue, and identify the problem. Once you identify it you can then examine ways to resolve it.
Let us know of any results you may have…
I hope this has been helpful!
Laz