The ER is designed to rule out the life-threatening is not so great for anything else.
May I suggest about the difficulty swallowing and chest pain, you may want to get a referral (which I think your family doctor will go along with) to a gastrointestinal specialist to get diagnostic testing to confirm or rule out the diagnosis of acid reflux? Esophageal spasms can feel like you are having a heart problem. Also, sense you are getting knots in your right chest, if it happens particularly after eating fatty or other foods that are hard on a gallbladder, ask for an abdominal ultrasound to take a look at your gall bladder and duct work.
With the knot in right chest, pressure and tightness, did they probe for a tender spot in your chest? Costochondritis can have some very scary symptoms (may I suggest taking a moment to look that up and see if you think it might fit), including hurting to breathe and feeling like you are having a heart problem. Believe me, I've wondered about my heart more than once where it turned out to be costochondritis.
Regarding your loss of breath during sleep, ask your doctor to refer you for sleep apnea testing. Extra pounds can often lead to this disorder where a person has numerous episodes while sleeping where they stop breathing.
Good for you to get exercising and changing eating habits to try and get to a healthy weight. But with your positive for RA and possible fibromyalgia, might I suggest (with your doctor's okay) a heated pool exercise program like at a YMCA, which is easier on your joints and can still provide a valuable avenue of exercise? I went to one where a coach at the Y told us what to do and had us taking our pulse also.
Since you had a recent flare up of swelling in a finger, you might want to travel back to (or get referred to) a rheumatologist about your positive RA and possible fibromyalgia.
Purchase a bottle of 150 gel caps of Capsicum or red chili pepper 35K or higher. Take one a day for 45 days and see where your blood pressure, strength and blood work have changed for the better.
Read the book .. "Left for Dead."
Regarding the headrushes when you eat (if you are not having a panic attack at the time or didn't just drink ice cold water too fast or something like that): You may want to get a home blood pressure monitor (Omron is a highly respected brand) and see what your blood pressure is doing. It is normal for it to elevate, but see if it is way high. Also, take your pulse when you feel it. Also, you might ask the doctor to ease your mind and encourage you that it's okay to exercise in your pursuit to get to a more healthy weight, if he/she would be willing to order nuclear medicine stress test.