Arm Feeling Heavy And Painful, Sore And Dry Throat, Chest Tightness And Heart Burn. What To Do?

Question: My left arm feels odd, it's heavy and it feels as if the pain is coming from inside my veins, I feel a tingliness/numbness that comes and goes, I've been very gassy lately as well (burping, farting) and my throat is sore and dry, I believe I might be experiencing some heart burn, I do sit at the computer quite a bit and have experienced slight chest tightness though I think that is more from fear than anything, also I'm 21 and female, the last time I had my heart checked was about 2 years ago and I was perfectly fine, I have normal to low blood pressure and no cholesterol issues.

Now that I've calmed down my arm does feel better however it still feels twitchy, like I am experiencing some very small muscle spasms. I'm still experiencing a dull pain near my shoulder, underarm near armpit and wrist of my left arm. Also before I felt as if the tips of my fingers were getting cold but this has gone away completely. Is this a stress related issue or signs of something more?

My throat feels better, not as sore, dry or itchy like before, is this due to allergies? I suspect that I could be experiencing a post-nasal drip however many allergy medications put me to sleep so is there something else I could do?

Often times when I stand up too quickly or stretch my arms all the way extended over my head I experience a head rush and feel very light headed, my eyes then feel extremely tired and unfocused, and my arms move very slowly back down but feel slightly numb is this due to slightly low blood pressure? Most of the time I'm somewhere near 100/70. Could this be an indicator of a pinched nerve?

I have had asthma since a very young age, probably 2 or 3 years old and sometimes I feel a sharp pain in my chest as if a very long needle is coming through my left side under my breast into my chest as well as from the back into my chest. Could these be stress related symptoms or perhaps related to my asthma or something completely different?

Thank you for your earlier response as it put me more at ease, I greatly appreciate your promptness as well.

Hello,

I rest my elbows or the area between my elbow and wrist on my desk while I'm typing, I'm usually there for most of the day. I also rest my head on my hand while my elbow is on the table. I just got scared that maybe this was a heart related issue because the tingliness/numbness and I'm also experiencing a slight burning sensation in my arm every now and again. When I stretch my arm up over my head and push it toward my neck I experience a heaviness to my arm, is this normal? I just want to make sure these symptoms are not anything serious or heart related.
If this is just a result of stress or muscle spasms, what should I do to make it better?

I do eat a lot of spicy foods and citric acid so I'm almost certain I have acid reflux. However, I'm confused about the chest pain, what do you mean by "following XXXXXXX inspiration" ?
I would also like to note that now I'm feeling a slight pain in my left thigh when I move a certain way, coming in from the back (or underneath) and it feels like its in my veins.
Thank you