I get reflux and take lansoprazole and gaviscon, which help somewhat. Also try not to eat too much at once and no big meals just before bedtime, etc.
My understanding is that while GORD can make the asthma worse by reflux of the acid into the trachea and lungs, the asthma medication can also make the reflux worse. The steroids can cause acid indigestion as many people will be only to well aware. Also bronchodilators like salbutamol, terbutaline and theophylline can have a dilating effect on the valve between the stomach and the oesophagus stopping it from preventing reflux of stomach contents up the oesophagus. Chronic hyperinflation of the lungs and high intrathoracic pressures with chronic severe asthma also has a dilating effect on the valve. Finally the weight gain that a lot of us experience due to pred and inactivity increases the risk of reflux. So it's a multifactorial problem really.
Drugs like lansoprazole and esomeprazole are usually pretty effective at controlling the symptoms in most people, so if you suffer from uncontrolled reflux and you're not on one of these drugs (they all end in 'prazole') it's worth a visit to your GP!
Prof Ayres has written a good paper on this topic which goes into the cause and effect as I've summarised above:
Hope this is helpful