Bruising results from breakage of capillaries, which causes blood to leak in to the tissues causing the discoloration. Capillary weakness generally results from either vitamin C or silica deficiencies. In your case it sounds more like a deficiency of vitamin C. This leads to poor adrenal function resulting in problems like low energy and immune suppression.
As for palpitations this can be caused from low blood pressure or cardiac irritability from decreased blood flow to the heart. If your blood pressure is chronically low then this can also be a sign of adrenal dysfunction. Magnesium, which acts as a calcium channel blocker, will actually drop your blood pressure further, so have it check it routinely for a week or so before doing anything.
If your blood pressure is normal then the palpitations could be from vasoconstriction, in which magnesium can help. I recommend magnesium malate, which will also improve muscle function, including the heart.
As for the burping and digestive problems, this is going to be from a lack of stomach acid. Stomach acid levels decline with age leading to the inability to absorb nutrients properly and to digest proteins. The protein digestive enzyme pepsin cannot function properly without sufficient stomach acid. The lack of stomach acid also leads to fermentation and thus the gas formation causing the burping. Digestive bitters can be used to increase digestive secretions that should decrease the fermentation. This will also cleanse the liver. You only need to taste the bitters to get the effect since the bitters stimulate the bitter receptors, which in turn stimulates the vagus nerve. This increases the digestive secretions and stimulates flushing of the liver. You should drink plenty of water throughout the day when using bitters.
I also recommend trimethylglycine (TMG) derived from beet leaves. Among its many effects is immune modulation and strengthening the digestive system. It is very safe, even in high doses. TMG can be found in health food stores or online. The same for the bitters I mentioned.
By the way, hair analysis is not accurate so don't depend on those findings. Different parts of the hair will have different readings. And external exposure can affect readings as will some shampoos.