from what I have researched and learned from doctors - constant gas and bloating can be due to poor/improper food digestion. Your body needs enzymes to break down food - especially meats and fats. Your body produces several types of enzymes - amylase (key for carbs), lactase (key for milk), protease, lipase, maltase, etc. etc. Your pancreas are responsible for secreting these enzymes. If you stress easily, or are older than 35 this production is reduced. Some people become lactose intolerant or start to have new food allergies. Now, if your body doesn't produce enough enzymes your food is not digested properly. Your body will start to break down the food using bacteria. Bacteria digestion causes fermentation and is inadequate, taxes the digestive system and makes it sluggish. So you can get lots of gas (burping if gas is produced in stomach, flatulence if from the intestines). Producing more enzymes naturally takes a while to train your body to do but it can be done. You can start by eating slowly to give your pancreas time to produce the enzymes. Chew your food a ton since saliva is a trigger for your stomach to prepare HCL & enzymes for digestion. Also, you decrease the amount of work your stomach does by breaking down the food as much as possible. Try to eat lots of greens that stimulate enzyme secretion - I believe alfalfa is good for this. Try eating warm foods & soups too - a huge effort is made by your digestive system to warm food up before it is digested. Eat simple meals - do not combine too many foods. Try eating 4 small meals instead of 3 big ones. Finally, if you feel like this may be your problem, ask your doctor or nutritionist about taking 1 - 3 digestion enzymes with every meal until you feel better. I like Enzymedica's Digest Gold. You can read reviews on them online - they have saved quite a few people.
If you feel like you may not be producing enough stomach acid, ask about taking HCL with Pepsin. I would try the enzymes for a couple of weeks first. If no result, try the HCL at one meal and see if you get relief or indigestion. If it does not agree with you, then acid production is not your problem.
For constipation, it can be caused by so many factors: fiber deficiency, dehydration, iron deficiency, poor peristalsis of colon, excessive fat or red meats in diet, etc, etc. Simplest solution is usually the easiest - increase fiber intake, replenish intestinal flora, eat foods that lubricate intestines.
If your diet permits, try a breakfast of oatmeal or muesli with cinnamon and psyllium or flax seeds or flax oil (or take 1 Tbspn organic, unrefined, cold pressed flax seed oil), and/or kefir (goat milk preferred since it is easier to digest than cow milk) with strawberries or mango or try papaya (it has digestive enzymes like papain). For lunch try eating a big salad with mixed greens and chicken breast and olive oil with lemon & a tiny bit of sea salt, and eat a lighter dinner like fish, or quinoa, brown rice with some steamed veggies. I mentioned kefir which is fermented milk because it offers so many benefits for your digestive system - it is fermented which means it has been predigested for you so most lactose intolerant people can handle it. It also has many probiotics which will help revitalize your intestinal flora. You can also try a good probiotic formula (buy the ones that have to be refrigerated). Most fermented food has the good bacteria you want in your intestines - kombucha, pickles, seaweed/Spirulina. To lubricate bowels eat spinach, bananas, sesame seed/oil, pear, prune, apple, almond, alfalfa, beets, seaweed, papaya, coconut, bran, cabbage, etc.
If you are desperate, or in the case of an emergency, try taking 2 - 4 Tbspn of Extra Virgin Olive Oil before a meal. You can also take a bath in 2 cups of Epsom Salts (Magnesium) for 20 minutes. You should go within 14 hours. You can also take Magnesium supplements (most people Mag deficient) but check with your doctor first. At mealtime, limit the amount of water you drink when you eat since this will dilute your digestive juices. Better to hydrate between meals.
Finally, exercise and relax!!!
Please confirm any changes you make with your doctor first. Encorporate changes slowly to see what works and what does not. I have no medical training. I only recommend what I have tried and worked for me so please check with your physician before taking any of my recommendations.
Best of luck!!!