All of them sound natural to me except #6. I would say instead:
Why is my stomach burning?
or
What is making my stomach burn?
One other note, though; even though Nos. 1-4 are worded okay, I would not call those "stomach problems." The phrase stomach problems is usually used to describe ailments like indigestion, as you did in Nos. 5 - 8. A growling tummy isn't really a stomach "problem," not in the way I usually hear stomach problems.
Is there any other word which is commonly used to describe stomach related problems?
There probably are, although I think you nailed the two most common ones with Nos. 7 & 8. Upset is often used when referring to the stomach organ, while bloated is sometimes used when referring to the lower abdomen in general, and may not be related to digestive problems at all. Sometimes you might hear the term GI used, particularly in the medical community (GI being short for gastrointenstinal). You can simply Google GI problems for a boatload of examples.
Shelter-half, rain fly, and leanto (or lean-to) are three terms sometimes used as names of a structure as in your picture. Scattered among images on the google-images pages (1,2,3) are some pictures like yours, although for the third term images like yours are infrequent. Also see tarp, tarp tent, and tarpaulin.
Among people who camp in the US, fly or rain fly is the accepted term for the outer layer of a tent-and-fly combination, where the fly serves as a rain shield or additional thermal barrier for the tent. Most multi-season camping tents come with a fly or offer one as an option. Flies for tents typically are shaped to roughly match a given tent (ie are not flat) and are sewn together from pieces of thin nylon fabric, often waterproofed. A tent and fly can be used in several combinations: the tent alone, in mild dry weather; the fly alone, as a quickly-set-up rain or sun or sleeping shelter; or in more-severe weather, used together, with the fly keeping the tent drier and warmer than it would otherwise be.
A tarp, on the other hand, may be made of canvas, nylon, or various combination fabrics (such as rubberized or plasticized nylon). Tarps typically are flat fabric, with grommets along the hems. A shelter-half is a particular kind of fly, such that two shelter-halves together can make up an enclosed tent. Shelter-halves have been common items in surplus stores after various wars, and while (in my opinion) they are practically obsolete, the term shelter-half lives on.
Best Answer
Yes, there is a term for that in English. It's called a growl:
There are actually a number of terms in English that are used to describe abdominal sounds (sometimes called bowel sounds) among which are words like gurgle, grumble, rumble et cetera, but growl is by far the most common. Here's another example straight from Oxford English Living Dictionaries (OELD):