The sorrow felt from the 3 of Swords is sudden and painful, and it is not a cut finger or a bad fall. Like most Swords it is about internal hurt, mental anguish and heartache (literally).
Look how tight those bonds are, what are we afraid to release? What would happen if we let go? Well, we would heal. But not until we have used an entire box of plasters, tons of painkillers and used 10 boxes of tissues from crying.
Release is the key for this card. Release in order to regenerate. Think of when you cut yourself, you bleed right? As soon as the cut is made your wonderful blood is going into survival mode and starts sending its own soldiers to the wound, and it starts to coagulate. In order to then form a scab that will stop the bleeding. Think of the scab as a shield.
The tight bond that is keeping the pain inside needs to be released, in order to form a shield that will allow us to restore our energies and heal.
In terms of a mental state this could be impulsive, like someone not wanting to release the pain, hence hurting themselves even more. The start of a depressive state, mood swings. But it will be temporary.
"No one ever told me that grief felt so like fear."