Hi @viragomann thanks for your support on this.
I could get it working, I just removed Custom options
push "dhcp-option DNS 192.168.3.1";
push "dhcp-option DOMAIN local.lan";
I saved changes and restarted the whole pfsense, it just started working after that restart, I mean the machines which are using OpenVPN can reach the machines which are in the LAN network by dns instead of IP addresses, my suspicion pfsense needed to be restarted and there was not any need by adding the Custom options, after that I wanted to double check this in other to have repeatable steps and what I could find out is that those enabled options in Dns Resolver such as DHCP Registration, Static DHCP, OpenVPN Clients as DNS Default Domain and Dns Server 1 in OpenVPN server settings are mandatory options in order to get it working, I know there could be a lot of ways to do this, I am just sharing with you how I could do it in this way