Greetings all.

I am a 30 year old trans-woman (pre op, no HRT yet), and over the course of the last 2-3 years, I haven't been able to shake off the feeling that I may have cancer, somewhere in my body.
Every day, at least once or twice, I always think about it.

I don't even know where to begin...
So, I smoked for 10 years, between 2009-2019. Roughly a 20 box a day (or the equivalent in hand-rolled cigarettes).
In 2019, I turned to vaping, in a bid to quit smoking. Thankfully, I haven't smoked a cigarette since. And now I'm only on 6mg (per 10ml bottle) of nicotine. So, the intake has been heavily cut down.
Also, I think it's worth mentioning that I had a problem with energy drinks between 2014 and 2019. I would drink roughly 4 cans a day. Dropped those too.
I have lived a somewhat sedentary lifestyle (until this year) for the last 8 (maybe?) years. Only going out skateboarding, or for a walk occasionally. But still doing daily shop runs.
Recently, I began to do exercise. Following suit from dropping my bad habits, to better my health. (Much needed as I need to lose some weight, seriously).

Where does the cancer come in?
First of all, back in 2014, I noticed a lump forming in the dead center of my chest, just beneath my pectorals.
I had this examined 3 years ago after it had grown quite a bit, and the nurse practitioner told me that it is very likely to be a lipoma. There's another lump towards the left of my ribs that is pea-sized that had formed not long before the examination, and the same thing was said about that. As the lumps aren't 'irregular'. (They're round and firm, and move a little under the skin).

Now, in the last two years, I have noticed that my bowel movements have went to pot.
Sometimes, I poop twice a day. Sometimes, I poop twice a week.
My stool is never consistent either. Most times, it is soft and mushy with a yellow hue (and smells absolutely foul), sometimes it may just be mucusy liquid, and very rarely I get a somewhat good-enough formed stool that is light brown.
Accompanying this half of the time, I get sharp stomach cramps. As soon as I get one of these cramps, I know it's time to go, and have to rush to the toilet.
Also, when I wipe, there's about a 60% chance there will be blood (likely caused by some sort of irritation, as I don't wipe gently, and my rectum stings a little when the blood is present).
Again, had this seen to a couple of years ago. Three times. 
First time, I described my symptoms, the doctor pinned it simply on IBS - I had my suspicions that's what it may be, and left it at that. Until the pain got worse about a year later, and I started feeling like I wasn't having complete movements. I had an anal examination at a hospital, and again, doctor said there was nothing dubious in my rectal canal, and that it was probably fecal impaction. Some time later, I began getting really bad pains all over my abdomen and rang 111. And was told (you guessed it) - IBS.
I'm beginning to believe that it may actually be Crohn's Disease? Given the absolute state of my bowel movements.

With my guts being my main concern right now, I also get pains in my left armpit, my left pectoral, in the left ribs, and the top corners of my stomach/abdomen (not the middle). And only in the last month or two, I have noticed that I get a pain in the center of my back and off to the left, that feels like a knot. I have put this down to possibly bad posture and age.

And as a minor concern (and the last one), I am rather flatulent.
I burp and fart to a 9:1 ratio, which may result in heartburn on the off-chance.
I have only been belching this badly for the last 2-3 years, and again, when consulting a doctor about some sharp chest pains, they told me that gas may be ricocheting off my diaphragm, and dispersing through my chest at speed, causing the pain.

TL;DR: I get a lot of pains around my chest and abdomen that I cannot explain. My bowel movements are shoddy, off-colour and foul-smelling. I have lumps that I can feel around my chest and abdomen. And I belch way more than a person should, that sometimes brings on heartburn.

I will close this post with this;
I have seen/rang doctors many times over the last 3 years regarding each separate ailment. And as I said, each time, I was given some explanation, and I feel like they're downplaying my issues. The only test I've ever had for any of this, is a finger up the backside.
I thought I would turn to a community who may be able to share some experiences, or shed some light on what I may be going through, as the anxiety is killing me.

A huge thank you in advance.
-Mira