Preheat the grill to medium-high heat.
In a small bowl, combine the softened butter, parsley, dill, chives, and minced garlic. Mix until well combined and set aside.
Pat the steelhead trout fillets dry with paper towels. Brush both sides with olive oil and season with salt and pepper.
Place the trout fillets skin-side down on the grill. Cook for about 4-5 minutes, then carefully flip and cook for an additional 3-4 minutes, or until the fish flakes easily with a fork.
During the last minute of cooking, spoon a generous amount of the herb butter over each fillet to melt.
Remove the trout from the grill and drizzle with lemon juice. Serve immediately with lemon wedges on the side.