Hi, I'm new to the forum but I've been vaping for about a year now. I've read other threads on this forum of people complaining about side effects, and I too have experience side effects from vaping, so I thought I would offer my advice. First, PG can F you up! I don't care what anyone says. I know some are immune to it but that's not the case for many. I have no allergies and have consumed plenty of food items with PG, but I cannot inhale that junk. PG makes my throat sore and dry, and makes my chest hurt worse than cigarettes. If you're having any problems with sore throat, sore lungs, or cotton mouth, switch to VG. In fact, I would suggest everyone vape VG exclusively simply because it is much, much safer. The mere fact that it is commonly used in herbal treatments and essential oils should be enough evidence. Secondly, nicotine levels. In my experience, all of the e-cig vendors I've dealt with on a local level are shady individuals that I do not trust, especially when it comes to advice about nicotine or any other chemicals. No offense to any vendors out there; this has just been my personal experience. I had one vendor tell me that an ordinary cigarette has 40mg of nicotine in it. Complete BS. Most cigarettes have less than 1mg of nicotine. So if you vape a ml of 36mg fluid over the coarse of a day, it's like you just smoked 36 cigs, except worse because you're getting a purer form of nicotine. Anyone who's ever vaporized ......... can attest that it is much more potent that way, and the same goes for vaporizing nicotine. For those that don't know the ratios, if the label on a bottle of e-juice says 24mg, that means there's 24mg per ml. So, again, a 30ml bottle would contain a total of 240mg of nicotine, which is A LOT. If you are having any type of sharp chest pains similar to what you might experience from a heart attack or angina attack, I strongly suggest lowering the level of nicotine you are vaping. I would suggest less than 12mg is safe range, but you should go even lower than that unless you are just so horribly addicted to nicotine that you need more. Nicotine is DANGEROUS. If you don't believe me, try to buy some pure nicotine. Good luck. You can't. It's a very potent stimulant and should be treated as such. You can think of it as caffeine. A very strong cup of coffee has about 100mg of caffeine in it, and we all know what that will do. Would you guzzle down 1,000mg of caffeine? No! Why? You'd have a heart attack. A very strong cig might have 1 - 3 mg of nicotine, so when you put 3 - 5 drops of 36mg fluid in your e-cig, you might as well pop 5 cigarettes in your mouth and light 'em up. Anyways, I've experienced the symptoms above, and these are the measures I've taken to fix them. Sore/dry throat: switched to VG, all good. Sharp/tight chest pains like my hear was gonna burst: drastically reduced my nicotine level, all good. Also, keep in mind that if you are a coffee/tea/soda drinker AND you are vaping, you are putting a lot of stimulants in your body. In some cases you might be better off vaping 0mg and having that one cigarette once in a while when you need it badly. Hope this helps anyone else who has had these problems.