Hello,
Thank you for asking at HCM.
I went through your history and would like to make suggestions for you as follows:
1. If you need 
Ventolin (a rescue inhaler to be used on as-and-when-needed basis) twice a day, it suggests that your 
asthma is not well controlled with controlled medications (such as 
Seretide 25/125 twice a day).
2. I usually prescribe my such patients additional 
montelukast on regular basis. Increasing dose of controller inhaler (Seretide) could be another possible option. I would suggest you to discuss this with your doctor and make a decision regarding how to improve asthma control.
3. Regarding 
chest pain, yes, such type of chest pain can occur in uncontrolled asthma. However, "heaviness of chest" can also occur in heart problems, gastric/esophageal problems and 
anxiety disorders.
Practically, if taking a rescue inhaler relieves your chest pain, it might be due to asthma. However, please remember that there are other possible causes also, which should be ruled out by your physician by detailed history, physical examination and appropriate investigations.
4. I would also suggest you 
allergy testing for common air-borne allergens such as house dust mites, pollens, molds, insect proteins, animal dander, etc. This will help you identify the substances causing allergies to you as well as to know the measures to avoid them.
5. In general, please avoid exposure to dusts, smokes and air pollution as much as possible.
6. Regular physical exercise including breathing exercises as well as nutrition rich in vitamins & minerals will also help you in a long run by improving your lung capacity and immunity respectively.
Hope above suggestions will be helpful to you.
Should you have any further query, please feel free to ask at HCM.
Wish you the best of the health ahead.
Thank you & Regards.