What is the treatment for esophageal achalasia?

Several. The main treatments are 1) medications, 2) endoscopic, and 3) surgical. Which one to choose depends on how severe the symptoms are.
Medical/surgical. Medical treatment is with calcium channel blockers. Endoscopic treatment is with balloon dilation of the lower esophageal sphincter, but typically has to be repeated several times. Surgical treatment is a heller myotomy. Your gastroenterologist can help you decide which treatment is best for you.
Opening the valve. All treatment for achalasia is aimed at permanently opening the valve entering the stomach. The most ineffective is Botox injection. Endoscopic dilation is ok, but not as good or permanent as surgically opening the valve, usually done laparoscopically. Endoscopic myotomy (cutting the muscle) is becoming more available. It is called poem - per oral endoscopic myotomy.
Surgery. There are alternatives, but surgery (heller myotomy) is the best and most lasting treatment. It can be done with minimally invasive techniques and recovery is fast.
Multiple options. Currently, there are multiple options for treating achalasia. Medications have limited success. Endoscopic treatment (via a flexible scope passed from the mouth into the esophagus) can be used to dilate (balloon pressure) or temporarily weaken (botox injection) the lower esophageal sphincter. Surgery involving laparoscopic release of the sphincter (myotomy) is a very good option for most patient.