Is there any way to call .NET Rest API after my queue item is processed?
Yes, you can call REST or SOAP api from uipath. Install UiPath.Web.Activities package so that you will get the activity as http request . @Umang_Mehta
Is it also possible to send notification to .NET Rest API from Uipath Orchestrator Webhook @HareeshMR ?
Ofcourse you can @Umang_Mehta, Webhooks are meant to send the data whenever it is available. But I haven’t tried that yet 
… Please check and let me know the process