Welcome to the Anxiety Forum. Your sx could all be caused by anxiety as just about anything can becaused by anxiety and chest pain is a frequent one that members speak of.
The most common type of tachycardia is sinus tachycardia, which is the body's normal reaction to stress.
You have done the right thing and been to your physicians. I am glad your tests were normal.
Reading your post makes me think you may have anticipatory anxiety.
Common Anticipatory Anxiety Reactions include :
Feelings: anxious, fearful, angry, confused, hopeless, losing control, numb, sad, moody, irritable, guilty.
Behaviors: withdrawal from others or activities, disrupted routines, startle reactions, easily crying
Cognitions: preoccupation with possibility of trauma, concentration difficulties, self-doubt, worry, indecisiveness, memory difficulties
Physical complaints: muscle tension, headaches, gastric distress, sleep and appetite changes, fatigue
Talking usually helps. Share your feelings with friends, family, on here are all good ways to work through the anxiety.
Relaxation techniques: Try deep breathing, muscle relaxation, visualization (imagining peaceful scenes), and/or listening to soothing music.
Realistic self-talk: While we can't always control what happens to us, we can always control what we say to ourselves. It's important to keep things in perspective. Talk to yourself in reasonable ways. Ask yourself "how likely is my fear?" Remind yourself that you have coped before during other challenging times. Don't just dwell on the negative but consciously look for things you can appreciate every day.
Make an effort to stay focused on what's happening now. What do you see, hear, and smell? How do you feel? Truly be 'present' in the moment! That will help you keep the anxiety down.
Please remember I am not a professional but I am a peer with the same problems you are having.
Take care and keep on posting to us.