You can start by looking on Archive of Our Own (AO3). It has a vast collection of fanfiction, and there are likely many 'dean hurts castiel' stories there. Fanfiction.net is also a good place to check.
One great 'dean hurts castiel fanfiction' could be 'The Broken Bond'. It delves into the emotional turmoil Dean experiences when he accidentally causes harm to Castiel. Another is 'Healing the Wounds' which focuses on how they both overcome the pain and strengthen their relationship.
There is also 'The Painful Betrayal' in this genre. In it, Castiel makes a decision that he believes is for the greater good but ends up emotionally hurting Dean. It shows their complex relationship and how they struggle to get back on track.
One common scenario in such fanfictions is when Dean's actions towards Castiel are influenced by his own internal struggles. Maybe he's dealing with self - loathing or fear of getting too close, and he takes it out on Castiel. This can really hurt Castiel who has been so loyal to Dean. As a result, Castiel may start to distance himself, which in turn makes Dean realize the magnitude of his mistake and start to make amends.
In dean - castiel relationship in such fanfiction, there's often a deep emotional connection. They might show a side of extreme vulnerability towards each other. Their relationship can be intense, with a lot of passion and a sense of 'destined to be together' kind of feeling.
Another excellent fanfiction is 'Heaven's Gatekeepers'. This one plays with the idea of their roles in the grand scheme of things in the Supernatural universe. It has a great plot that weaves in and out of canon events, and the way it portrays Dean and Castiel's connection is both unique and captivating.
One great aspect of Castiel and Dean in fanfiction is their dynamic. Their relationship, which is complex in the show, can be explored even further in fanfictions. Writers often delve into their unspoken bond, creating scenarios where they support each other in ways not shown in the original series. For example, some fanfictions might have them going on a road trip together just for the sake of exploring new places and having deep conversations about their pasts and futures.
There's also 'Wings and Hunters'. This one is unique as it focuses on a different aspect of their relationship, almost like a what - if scenario. It imagines a world where their connection is tested in ways that are both exciting and heart - wrenching. The story has a great flow and the descriptions are vivid.
There's also 'Dean, Castiel and Baby: A New Bond'. This fanfiction focuses on how Castiel, in his new 'baby' form, starts to understand human emotions better through his interactions with Dean. It has a unique take on their relationship and is quite engaging.