The white streak on the right edge appears to be the contrails from a jet airplane flying in the lower edges of the stratosphere.

The hexagonal dots in the middle of the picture are called lens flare. They're caused by a bright light source not far outside the frame. In this case, judging from the shadow cast by the rock on the beach, the sun is just to the right and above the edge of the field of view. Even though the sun is not in the picture, some of its light is shining at an angle onto the front of the lens. That light is bouncing around inside the lens causing lensing flare. The hexagonal shape is a result of your lens' aperture diaphragm, which has six blades.

The best way to deal with flare caused by strong light sources out of frame is to use a lens hood. If your lens is a zoom lens, though, the hood only provides optimal shading at the widest focal length. As you zoom in, you may need to shade the lens from the sun using a piece of cardboard or other opaque material.