I have a brown scar between my chest from a yeast infection that lasted years. Can laser removal get rid of this scar? (Photo)

This is not a scar, this is something called Acanthosis Nigricans or CARP.  This needs medical treatments combined with peels or Clear + Brilliant laser and microneedling.  You need to see a skin care expert with laser training to treat this.  There is no "cure" but you will get signficant improvement.  Best, Dr. Emer.

Some discoloration on the chest can occur from fungal infections. If this is ruled out, then application of a skin lightener such as Plato's Dark Scar Corrector can help. Best, Dr. Karamanoukian Los Angeles

This darkening represents post-inflammatory hyperpigmentation (PIH). It is not uncommon for inflammation (related to natural healing, trauma, infection, etc) to stimulate pigment production, especially if the inflammation is long-standing or chronic. UV radiation from sun or tanning bed exposure can make this process worse. Patients with darker skin pigmentation are also at greater risk for PIH.I think this hyperpigmentation is going to be very difficult to improve. Topical bleaching creams that contain some sort of ingredient(s) that blocks or interferes with pigment production (hydroquinone, kojic acid, etc) may provide some lightening in color. Retinol may provide some help as well, providing it is not too irritating. Sun preotection is also very important.I would suggest you consult with a board certified plastic surgeon for a thorough history and exam, to then discuss your options. If you are considering any type of light-based treatment  (laser, etc) I think it is very important to prep the area  ahead of time to reduce the risk of PIH.Best wishes