Handling multiple rows in SQL Server trigger

Handling multiple rows in SQL Server trigger

We have a database with a table called WarehouseItem where product's stock
levels are kept. I need to know when ever this table get's updated, so I
created a trigger to put the primary key of this table row that got
updated; into a separate table (like a queue system).
This is my trigger:
IF ((SELECT COUNT(*) FROM sys.triggers WHERE name = 'IC_StockUpdate') > 0)
DROP TRIGGER [dbo].[IC_StockUpdate]
GO
CREATE TRIGGER [dbo].[IC_StockUpdate] ON [dbo].[WarehouseItem]
AFTER UPDATE
AS
BEGIN
-- Get Product Id
DECLARE @StockItemID INT = (SELECT ItemID FROM INSERTED);
DECLARE @WarehouseID INT = (SELECT WarehouseID FROM INSERTED);
-- Proceed If This Product Is Syncable
IF (dbo.IC_CanSyncProduct(@StockItemID) = 1)
BEGIN
-- Proceed If This Warehouse Is Syncable
IF (dbo.IC_CanSyncStock(@WarehouseID) = 1)
BEGIN
-- Check If Product Is Synced
IF ((SELECT COUNT(*) FROM IC_ProductCreateQueue WHERE
StockItemID = @StockItemID) > 0)
BEGIN
-- Check If Stock Update Queue Entry Already Exists
IF ((SELECT COUNT(*) FROM IC_StockUpdateQueue WHERE
StockItemID = @StockItemID) > 0)
BEGIN
-- Reset [StockUpdate] Queue Entry
UPDATE IC_StockUpdateQueue SET Synced = 0
WHERE StockItemID = @StockItemID;
END
ELSE
BEGIN
-- Insert [StockUpdate] Queue Entry
INSERT INTO IC_StockUpdateQueue (StockItemID, Synced)
VALUES
(@StockItemID, 0);
END
END
ELSE
BEGIN
-- Insert [ProductCreate] Queue Entry
INSERT INTO IC_ProductCreateQueue (StockItemID, Synced)
VALUES
(@StockItemID, 0);
-- Insert [StockUpdate] Queue Entry
INSERT INTO IC_StockUpdateQueue (StockItemID, Synced) VALUES
(@StockItemID, 0);
END
END
END
END
GO
This works perfectly fine, if only a single row is updated in the
"WarehouseItem" table. However, if more than one row is updated in this
table, my trigger is failing to handle it:

Is there a way to iterate through the "inserted" collection after a mass
update event? Or how does one handle multiple row updates in trigger?